The Chinese authorities have banned the phrase 'big yellow duck' as an internet search item after a prankster substituted tanks for ducks in a doctored version of a world famous photograph taken during the Tiananmen massacre . China has begun an annual crackdown on efforts by families to commemorate the . victims of the Tiananmen Square massacre, 24 years after the . pro-democracy demonstrations were crushed by the People’s Liberation . Army. A number of internet search terms have been banned including 'tomorrow' "today", "tonight", "June 4" and other number combinations that might refer to what the Chinese call the June Fourth Incident . Scroll down for video . Censored: The Chinese authorities have banned the phrase 'big yellow duck' as an internet search item after a prankster substituted tanks for ducks in this doctored version of a world famous photograph . Tank man: The world famous image of a protestors standing in front of oncoming Chinese tanks during the 1989 protests . Popular: The doctored photograph is a reference to the 54-foot yellow duck created by Florentijn Hofman, which floats in Hong Kong's Victoria Harbour. This shows a copy of the duck in Tianjin, China . As reported by International Business Times, 'Big yellow duck'  has also been censored as a search item. It comes after a user on Sina Weibo, a Chinese social network, posted a doctored version of the famous  Jeff Widener's  photograph of a protester confronting a line of tanks in the square. The doctored photograph instead features four ducks in row instead of the tanks. it was a reference to the 54-foot yellow duck created by Florentijn Hofman, . which floats in Hong Kong's Victoria Harbour. Families of the victims of the massacre have been barred from visiting their graves by more than a dozen Chinese police stationed outside the main 'Stone Gate' entrance to the Wanan graveyard where many of the victims are buried. The exact number of victims of the massacre on June 3-4 and the political crackdown which followed soon after is unknown but it is believed to run well into the hundreds if not more. Commemoration: Tens of thousands of people joined a candlelit vigil in Hong Kong to mark the anniversary of the Tiananmen Square protests today . Crowds: Demonstrators swarmed the city's Victoria Park in memory of the brutal crackdown carried out by the Chinese government . Freedom: The commemorations have only been allowed to take place in Hong Kong amidst heightened security in mainland China . Vibrant: Protesters brought a series of eye-catching banners aimed at undermining the government's anti-democratic policies . The Chinese Government considers the peaceful protest . by students and workers to have been a 'counter-revolutionary' revolt, . and has previously defended the decision to send in tanks and troops. It has never provided an official death toll. The move by Beijing is . part of a major push to suppress discussion of the massacre across China and Hong Kong, particularly online and around . certain parts of the capital. Security personnel were patrolling . the narrow streets close to Beijing's Forbidden City and outside the former . house of Zhao Ziyang, the Communist party secretary who was purged and . held under house arrest following the protests. Authorities have also detained or . enhanced surveillance on 10 prominent dissidents, according to the Hong . Kong-based advocacy group China Human Rights Defenders. Hardy: Protesters braved the elements to show their opposition to the military crackdown which killed the Chinese democracy movement . Passion: A man brandishes a candle as he protests next to a statue depicting the 'Goddess of Democracy' in Hong Kong . Moving: But in mainland China the authorities have blocked sensitive search terms to avoid controversy . Repression: Some protesters sat behind bars to symbolise the Chinese government's hardline authoritarian policies . Online . searches for a range of keywords on Sina Weibo, China's version of . Twitter, have been blocked, from ‘Tiananmen’ to ‘candle’, which has been used to . encourage digital vigils. Instead activists turned to overseas websites to commemorate the event and criticise authorities. ‘The . dispute in this country is basically stuck on whether to light a candle . or to extinguish it,’ dissident artist Ai Weiwei posted on Twitter. Rights . lawyer Liu Xiaoyuan said on Twitter that he had been blocked from Sina . Weibo for seven days for sharing 'sensitive information' -- urging . others to honour victims by posting an image of a lit candle. Forum: Participants at a discussion meeting in Victoria Park in front of a poster of Beijing's Tiananmen Square . Tributes: Wreaths left in Hong Kong to commemorate the iconic events of the 1989 protests . Security: There was a heavy police presence in Tiananmen Square itself to prevent the possibility of a memorial protest . A . mocked-up picture was circulating online of the 1989 ‘Tank Man’ photograph of a civilian staring down a long row of tanks headed toward . Tiananmen Square -- with the military vehicles replaced by plastic . ducks. The image could not be found on domestic websites within the . ‘Great Firewall of China’ as the country's system of internet controls . is known. The high-profile dissident Hu Jia wrote on Twitter the . broad crackdown on discussion of Tiananmen demonstrated the . government's weakness. The event underscored the ruling Communist . Party's ‘illegal nature’, he wrote. ‘The unprecedentedly high pressure . for the 24th anniversary of June 4 actually reveals the authorities' fear.’ Contrast: Chinese tourists in the square seemed carefree today; many are unaware of what happened in 1989 . Innocent: A little girl holding the Chinese national flag dances in Tainanmen Square as the portrait of Chairman Mao looks on . Over the weekend China accused the US of 'prejudice' after it urged Beijing to provide a full account of the crackdown on activists after the Tiananmen Square protests. Foreign ministry spokesman Hong Lei said the US should 'stop interfering in China's internal affairs'. The Chinese authorities had already reached a 'clear conclusion' about the Tiananmen Square protests, he added. On Friday, the US state department said the 24th anniversary of the 'violent suppression of demonstrations in Tiananmen Square' prompted it to remember this 'tragic loss of innocent lives'.
Chinese police stationed outside cemetery where victims of Tiananmen are buried .
Authorities blocking Chinese Twitter searches of sensitive terms related to historic demonstrations .
Chinese dissidents including artist Ai Weiwei criticise Beijing for censorship .
Streets of Hong Kong packed with protesters as pro-democracy residents demonstrate against crackdown .
The Chinese authorities have banned the phrase 'big yellow duck' as an internet search item after a prankster substituted tanks for ducks in a doctored version of a world famous photograph taken during the Tiananmen massacre . China has begun an annual crackdown on efforts by families to commemorate the . victims of the Tiananmen Square massacre, 24 years after the . pro-democracy demonstrations were crushed by the People’s Liberation . Army. A number of internet search terms have been banned including 'tomorrow' "today", "tonight", "June 4" and other number combinations that might refer to what the Chinese call the June Fourth Incident . Scroll down for video . Censored: The Chinese authorities have banned the phrase 'big yellow duck' as an internet search item after a prankster substituted tanks for ducks in this doctored version of a world famous photograph . Tank man: The world famous image of a protestors standing in front of oncoming Chinese tanks during the 1989 protests . Popular: The doctored photograph is a reference to the 54-foot yellow duck created by Florentijn Hofman, which floats in Hong Kong's Victoria Harbour. This shows a copy of the duck in Tianjin, China . As reported by International Business Times, 'Big yellow duck'  has also been censored as a search item. It comes after a user on Sina Weibo, a Chinese social network, posted a doctored version of the famous  Jeff Widener's  photograph of a protester confronting a line of tanks in the square. The doctored photograph instead features four ducks in row instead of the tanks. it was a reference to the 54-foot yellow duck created by Florentijn Hofman, . which floats in Hong Kong's Victoria Harbour. Families of the victims of the massacre have been barred from visiting their graves by more than a dozen Chinese police stationed outside the main 'Stone Gate' entrance to the Wanan graveyard where many of the victims are buried. The exact number of victims of the massacre on June 3-4 and the political crackdown which followed soon after is unknown but it is believed to run well into the hundreds if not more. Commemoration: Tens of thousands of people joined a candlelit vigil in Hong Kong to mark the anniversary of the Tiananmen Square protests today . Crowds: Demonstrators swarmed the city's Victoria Park in memory of the brutal crackdown carried out by the Chinese government . Freedom: The commemorations have only been allowed to take place in Hong Kong amidst heightened security in mainland China . Vibrant: Protesters brought a series of eye-catching banners aimed at undermining the government's anti-democratic policies . The Chinese Government considers the peaceful protest . by students and workers to have been a 'counter-revolutionary' revolt, . and has previously defended the decision to send in tanks and troops. It has never provided an official death toll. The move by Beijing is . part of a major push to suppress discussion of the massacre across China and Hong Kong, particularly online and around . certain parts of the capital. Security personnel were patrolling . the narrow streets close to Beijing's Forbidden City and outside the former . house of Zhao Ziyang, the Communist party secretary who was purged and . held under house arrest following the protests. Authorities have also detained or . enhanced surveillance on 10 prominent dissidents, according to the Hong . Kong-based advocacy group China Human Rights Defenders. Hardy: Protesters braved the elements to show their opposition to the military crackdown which killed the Chinese democracy movement . Passion: A man brandishes a candle as he protests next to a statue depicting the 'Goddess of Democracy' in Hong Kong . Moving: But in mainland China the authorities have blocked sensitive search terms to avoid controversy . Repression: Some protesters sat behind bars to symbolise the Chinese government's hardline authoritarian policies . Online . searches for a range of keywords on Sina Weibo, China's version of . Twitter, have been blocked, from ‘Tiananmen’ to ‘candle’, which has been used to . encourage digital vigils. Instead activists turned to overseas websites to commemorate the event and criticise authorities. ‘The . dispute in this country is basically stuck on whether to light a candle . or to extinguish it,’ dissident artist Ai Weiwei posted on Twitter. Rights . lawyer Liu Xiaoyuan said on Twitter that he had been blocked from Sina . Weibo for seven days for sharing 'sensitive information' -- urging . others to honour victims by posting an image of a lit candle. Forum: Participants at a discussion meeting in Victoria Park in front of a poster of Beijing's Tiananmen Square . Tributes: Wreaths left in Hong Kong to commemorate the iconic events of the 1989 protests . Security: There was a heavy police presence in Tiananmen Square itself to prevent the possibility of a memorial protest . A . mocked-up picture was circulating online of the 1989 ‘Tank Man’ photograph of a civilian staring down a long row of tanks headed toward . Tiananmen Square -- with the military vehicles replaced by plastic . ducks. The image could not be found on domestic websites within the . ‘Great Firewall of China’ as the country's system of internet controls . is known. The high-profile dissident Hu Jia wrote on Twitter the . broad crackdown on discussion of Tiananmen demonstrated the . government's weakness. The event underscored the ruling Communist . Party's ‘illegal nature’, he wrote. ‘The unprecedentedly high pressure . for the 24th anniversary of June 4 actually reveals the authorities' fear.’ Contrast: Chinese tourists in the square seemed carefree today; many are unaware of what happened in 1989 . Innocent: A little girl holding the Chinese national flag dances in Tainanmen Square as the portrait of Chairman Mao looks on . Over the weekend China accused the US of 'prejudice' after it urged Beijing to provide a full account of the crackdown on activists after the Tiananmen Square protests. Foreign ministry spokesman Hong Lei said the US should 'stop interfering in China's internal affairs'. The Chinese authorities had already reached a 'clear conclusion' about the Tiananmen Square protests, he added. On Friday, the US state department said the 24th anniversary of the 'violent suppression of demonstrations in Tiananmen Square' prompted it to remember this 'tragic loss of innocent lives'.
to commemorate the . victims of the Tiananmen pro-democracy demonstrations were crushed by the more than a dozen Chinese police stationed Wanan graveyard where many of the victims are blocked sensitive search terms to avoid artist Ai Weiwei posted on Twitter. Rights . left in Hong Kong to commemorate the iconic the . broad crackdown on discussion of Tiananmen