Vladimir Putin today demanded an end to 'shameful' political assassinations in the wake of the shooting of a Kremlin critic last week. Boris Nemtsov, a former deputy prime minister, was gunned down as he walked with his Ukrainian girlfriend on Friday night near Red Square. He was the most prominent opposition figure to be killed in Russia during Putin's 15-year rule. The Kremlin has denied any involvement, saying that the killing was a 'provocation' designed to discredit Putin and strengthen his opponents. Scroll down for video . Russian President Vladimir Putin attends an Interior Ministry board meeting in Moscow, where he called for an end to the 'shame' of political killings which have plagued the Kremlic in recent years . Gunned down: Nemtsov (left) and his 23-year-old model girlfriend, Anna Duritskaya (right) were walking through Moscow after having dinner on Friday night when he was shot four times in the back . But Nemtsov's friends say the Kremlin is to blame for fomenting an atmosphere of hatred towards its opponents. In a speech during a meeting with officials from the interior ministry, Putin said: 'The most serious attention should be paid to high-profile crimes, including the ones with a political subtext. 'Russia should be devoid at last of the kind of shame and tragedies that we have recently endured and seen. 'I mean the murder, the audacious murder of Boris Nemtsov right in the centre of the capital.' Law enforcement officials have said one lead they were exploring was that the killing was linked to Nemtsov's personal life or business dealings. Putin's comments indicated that version is now being discarded. Authorities have not made any arrests. Honoured: People  applaud as workers carry the coffin of Kremlin critic Boris Nemtsov during a ceremony at the Sakharov centre in Moscow, where his body was laid in state after he was shot dead on Friday . Goodbye: Nemtsov's mother Dina Eidman, his secretary Inna Krolyova and daughter Dina (from left to right) pay their last respects at the mourning ceremony . Earlier on Wednesday, the director of Russia's Federal Security Service said that an investigation had identified several suspects, without giving details. Russian news agencies reported that investigators were seeking a car in connection to the killing that may be connected to the finance ministry. The ministry said in a statement sent to Reuters that the car, a Ford, does not belong to the ministry itself but was owned by a state enterprise which provides security to government institutions, including the finance ministry. The vehicle drove past the spot where Nemtsov was shot after the killing and when police patrol cars had already arrived at the scene, the statement said. Thousands of Russians yesterday paid their final respects to Nemtsov  when he was laid to rest in the capital. The politician's mother Dina, 87, and four children laid him to rest, with ex-UK prime minister Sir John Major leading Western mourners attending his funeral.
PM says Russia 'should be devoid of tragedies with a political subtext'
Former deputy PM Nemtsov shot near Moscow's Red Square last week . Supporters blame Kremlin for fostering atmosphere of hatred for critics . Putin's comments suggest his killing was not linked to his personal life .