U.S. Vice President Joe Biden Biden called on Ukrainian President Viktor Yanukovych to immediately pull back police, snipers, military, paramilitary and irregular forces, the White House said Thursday.

Biden spoke by phone with Polish Prime Minister Donald Tusk on Thursday to discuss violent protests in Ukraine that have killed 75 people, the White House said.

"They discussed steps the United States, Poland, and the European Union are taking to support an end to the violence and a political solution that is in the best interests of the Ukrainian people," the White House said in a statement.

Ukrainian opposition leaders and president Viktor Yanokovich met at the negotiations table with mediation of foreign ministers from France, Germany and Poland, a Polish foreign ministry spokesman said.

"Talks of Polish, German, French foreign ministers at Yanukovych's office still going on. The opposition leaders, the parliament's speaker, many MPs attend," spokesman Marcin Wojciechowski, who is in Kiev with Polish Foreign Minister Radoslaw Sikorski, wrote in a Twitter post.

As a day marked by a severe escalation in violence approached its end in Kiev, with at least 75 killed, a forum of European foreign ministers announced a move to impose sanctions on those responsible for the violence.

"The decision is to proceed very rapidly, in the next hours, to a visa ban and asset freezes on those who have committed the violence," Italian Foreign Minister Emma Bonino told reporters as she left an emergency gathering in Brussels.

Bonino said the position had been agreed with the French, German and Polish foreign ministers, who are currently in Kiev negotiating with Ukrainian President Viktor Yanukovych.

"Progress made but important differences remain," Polish Foreign Minister Radoslaw Sikorski tweeted on Thursday evening, while on his way from a meeting with opposition heads to one with the Ukranian president.

Thursday's clashes erupted shortly before the ministers were due to meet the Russian-backed Yanukovych to push for a compromise with his pro-European opponents. The meeting was delayed for security reasons but began an hour late.

President Barack Obama and German Chancellor Angela Merkel spoke by telephone Thursday to discuss the spiraling death toll. "They agreed that it is critical that the United States, Germany and the European Union continue to stay in close touch in the days ahead on steps we can take to support an end to the violence and a political solution that is in the best interests of the Ukrainian people," the White House said in a statement.

next previous 9 of 9 | Anti-government protesters take cover as they are under fire reportedly of police sniper during clashes police in the center of Kiev on February 20, 2014. Credit: AFP 1 of 9 | Protesters advance towards new positions in Kiev on February 20, 2014. Credit: AFP 2 of 9 | Ukrainian Cossacks play drums on Kiev's Independence Square, calling on people to protest. February 20, 2014. Credit: AFP

'They are shooting to kill'

The Ukrainian Health Department stated that at least 75 people were killed. Doctors working on Kiev’s Independence Square, however, claimed that as many as 70 people were killed on the rioters’ side alone on Thursday.

The death toll in the most violent wave of clashes between the rioters and the police in Kiev is likely to increase, as there are conflicting figures coming from the Health Department, city officials and the opposition.

As many as 550 people have been injured, according to official estimates.

Ukraine's Interior ministry said protesters captured 67 police troops in Kiev. Video footage on Ukrainian television showed protesters apparently leading some of the captured policemen around the sprawling protest camp in the center of the city. One opposition lawmaker said the police are being held in Kiev's city hall, which is being occupied by protesters.

A statement from Yanukovych's office earlier Thursday said: "They (the protesters) went on to the offensive. They are working in organized groups. They are using firearms, including sniper rifles. They are shooting to kill.

"The number of dead and injured among police officers is dozens," the statement on the presidential website said.

Ukrainian anti-government protesters on Thursday seized back control of Kiev's Independence Square, television reports showed, after fresh clashes broke out there with riot police.

TV pictures showed protesters surging forward into areas that were on Wednesday occupied by riot police after a day of violence. Several captured police officers were seen being led away by men in battle fatigues.

Russia not cancelling aid

Russian President Vladimir Putin spoke to German Chancellor Angela Merkel and British Prime Minister David Cameron by telephone on Thursday and they all expressed "utmost concern" over the deadly violence in Ukraine, the Kremlin said.

"Vladimir Putin stressed the critical importance of an immediate end to bloodshed, the need to take urgent measures to stabilise the situation and suppress extremist and terrorist attacks," the Kremlin said in a statement on its website.

Russia is not canceling a second tranche of financial aid to Ukraine but the situation must normalize first, President Vladimir Putin's spokesman, Dmitry Peskov, was quoted as saying by RIA news agency on Thursday.

Putin promised to lend cash-strapped Ukraine $15 billion and reduce gas prices in a bailout package seen as a reward for Kiev's November decision to scrap plans for political and trade deals with the European Union and improve ties with Russia.