BEIJING—China has been bolstering defenses along its 880-mile frontier with North Korea and realigning forces in surrounding regions to prepare for a potential crisis across their border, including the possibility of a U.S. military strike. 
 
 A review of official military and government websites and interviews with experts who have studied the preparations show that Beijing has implemented many of the changes in recent months after initiating them last year. 
 
 ... ||||| (CNN) China is further fortifying its northern border region, which includes North Korea, amid continued tensions on the Korean Peninsula and concerns over potential US military action against Pyongyang. 
 
 The North Korean-Chinese border stretches 880 miles (1,415 kilometers) across China's Liaoning province, an industrial and mining heartland prone to heavy smog and painfully cold winters. 
 
 In more hospitable months, the border city of Dandong plays host to hundreds of tourists coming to gawp at North Korea -- from boats on the Yalu River which separates the two countries, or through binoculars on a section of the Great Wall overlooking the international boundary. 
 
 Can China help the US deal with North Korea? 
 
 Can China help the US deal with North Korea? 02:18 
 
 Can China help the US deal with North Korea? 
 
 Below the tourists, trucks carrying Chinese goods rumble into North Korea as a small number of shoppers and traders head in the opposite direction. 
 
 But recent reports published on Chinese military and government websites, first highlighted by the Wall Street Journal , show Beijing is moving to reinforce the border as tensions on the Korean Peninsula rise and some in the US call for regime change in Pyongyang. 
 
 Chinese vendors sell North Korea and China flags on the boardwalk next to the Yalu river in the border city of Dandong in China's Liaoning province. 
 
 High security 
 
 According to a report published last month on the official website of the People's Liberation Army (PLA), a "newly formed border defense brigade" is conducting patrols to gather intelligence, assess the situation and more accurately map out the border region -- which includes North Korea, Russia and Mongolia. 
 
 Another report said the "whole area" has newly been placed under "24-hour video surveillance" including drones, patrol cars and high-tech cameras. 
 
 The North Korea border region is a highly strategic one for China, and has seen conflict during World War II and the Korean War, but one of Beijing's chief concerns is not military forces pouring across the border, but refugees. 
 
 "A mass movement of North Korean civilians across the border into China is a major concern, particularly given the dense population centers not far from the border, and the economic importance of Northeast China," according to a recent report by the US-based Jamestown Foundation. 
 
 While North Korea has proved remarkably capable of shrugging off economic sanctions, the country has suffered major famines and widespread food insecurity in the past, analysts say a conflict on the peninsula would likely result in hundreds of thousands, if not millions, of civilians heading north into China, the specter of which is a "huge worry for Beijing" according to the Council on Foreign Relations. 
 
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 Just as the Syrian refugee crisis has strained the resources of neighboring countries and caused widespread political strife in Europe, many in China are concerned by the hit the country's economy and security could take from even a small conflict on the Korean Peninsula. 
 
 "The stakes are huge," retired US Adm. Mike Mullen said last year . "Instability generated on the peninsula could cascade into China, making China's challenge of providing for its own people that much more difficult." 
 
 In March, retired PLA Major General Wang Haiyun said it was "necessary to prepare military action as soon as possible for a potential war" on the peninsula. 
 
 "Once war breaks out, we should also consider setting up an international refugee camp in North Korean territory to prevent the influx of North Korean refugees," said Wang in an op-ed in the state-owned Global Times. 
 
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 Warnings of war 
 
 Tensions between Pyongyang and Washington have continued to rise amid recent claims by North Korea that it had tested a nuclear-capable intercontinental ballistic missile (ICBM) 
 
 A US defense official told CNN this week North Korea appeared to be preparing for another test 
 
 The Donald Trump administration has sought to bring pressure on China to take action to contain its ally, but despite repeated condemnations by Beijing of North Korea's weapons testing, little progress appears to have been made. 
 
 Beijing has also criticized the US and South Korea for their rhetoric on the issue and encouraged all parties to return to the negotiating table. 
 
 However, such an invitation from Seoul to Pyongyang to resume talks went unanswered this month 
 
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 The situation has led to frustration on all sides, with Trump's CIA director Mike Pompeo last week appearing to indicate support for regime change in Pyongyang 
 
 Tong Zhao, an analyst at the Carnegie Tsinghua Center for Global Policy, said that "given the growing tensions and risks of military conflicts over the peninsula, I am sure China has been enhancing its military contingency plans." 
 
 On Monday, a Chinese Ministry of Foreign Affairs (MOFA) spokesman said "military means should not be an option to solve the Korean Peninsula issue." A Defense Ministry spokesman declined to comment Monday on China's war contingency plans. 
 
 Speaking Tuesday, MOFA spokesman Lu Kang said the country's military "has maintained normal combat readiness and training status along the Chinese-North Korean border." 
 
 Earlier this year, the Chinese state-run tabloid Global Times warned "if the North Korean nuclear issue boils over, a war on the peninsula is unavoidable."
– China is ramping up its military presence on its 880-mile border with North Korea in case a nuclear, economic, or military crisis sends millions of North Koreans fleeing in search of greener pastures, according to government websites. But as the Wall Street Journal reports, that might not be all China is preparing for. China's Defense Ministry hasn't referred to North Korea as the reason for a new border defense brigade along with a 24-hour video surveillance system, unit upgrades, new shelters and command posts, and recent live-fire and special forces drills in border regions; but experts say China could be preparing to intervene should the US attempt to seize nuclear weapons from its ally on the Korean Peninsula. Some aren't so sure China would be keen to take on the US and stress that recent enhancements at the border were first discussed last year. However, "once you start talking about efforts from outside powers, in particular the United States and South Korea, to stabilize the North ... you’re starting to look at a much more robust Chinese response," argues a former US defense official for East Asia. "If you’re going to make me place bets on where I think the US and China would first get into a conflict ... it’s the Korean Peninsula." Others note China will want to prevent US influence there to retain its regional power. In a column in May, retired Maj. Gen. Wang Haiyun wrote China should not only intervene in a Korean conflict but demand no US occupation of North Korean territory, though he said he did not speak for the government. He made similar comments in an op-ed in the state-owned Global Times in March, CNN reports.