With at least 21 civilians killed, dozens of police dead or wounded and an overnight truce in shatters, events in Ukraine moved quickly on Thursday.
European Union officials told news agencies late Thursday that the 28-country bloc's foreign ministers had agreed to impose visa bans, asset freezes and restrict the export of anti-riot equipment to Ukraine.
Vice President Joe Biden and Ukrainian President Yanukovych spoke by phone on Thursday evening, but details of their conversation were not released.
German Chancellor Angela Merkel and President Barack Obama had earlier discussed possible steps toward ending the violence in Kiev, also during a phone call, Reuters reported.
The latest developments came after it emerged that Merkel had telephoned Ukrainian President Viktor Yanukovych on Thursday to urge him to accept an offer from the EU, Germany and other partners to support talks between the Kiev government and opposition after violence escalated once more on Thursday.
Later Thursday, a statement from the Kremlin announced that Russian President Vladimir Putin was sending an envoy to Ukraine at the request of President Viktor Yanukovich, to try to mediate talks between the government and opposition.
Yanukovich telephoned Putin and asked him "to send a Russian representative to Kiev," the Kremlin said in a statement.
"Vladimir Putin decided to send human rights ombudsman Vladimir Lukin on this mission," it said.
The flurry of diplomatic activity follows another day of violence in Ukraine after Yanukovych had announced late Wednesday that a truce with the opposition had been reached,
However, violence broke out once more on Thursday morning just before three visiting European foreign ministers were set to meet with Yanukovych, forcing their meeting to be delayed and moved for security reasons.
(Read more: Ukraine clashes kill 21 more, EU talks shifted)
The protests began back in November after President Viktor Yanukovych's government rejected an accord with the European Union in favor of stronger ties with Russia.
Many were angered that Yanukovych had abandoned the country's two-decade long attempt to integrate with Europe following the collapse of the USSR, with thousands pouring into Kiev where they have occupied Independence Square ever since.
Following the latest battles on Thursday morning, in which a Reuters photographer counted 21 bodies, thus bringing the death toll since Tuesday to 43, the Ukraine presidency blamed the protesters for starting the violence and using snipers which resulted in clashes with police.
A joint statement from the EU and U.S. ambassadors in Ukraine read: "A meaningful dialogue must be established immediately to address the concerns of the Ukrainian people and prevent further loss of life. The protection of human lives should be the highest priority at this moment."
Timothy Ash, the head of EM (ex-Africa) research at Standard Bank in London, said in an a note: "Things (are) moving very fast...this can go in any direction."
(Read more: Six boiling cauldrons around the world)
Otilia Dhand of Teneo Intelligence said that the truce from last night was always going to be "questionable, not only because many doubt Yanukovych's sincerity, but also because the opposition does not necessarily have that much control over the crowd at the moment.
Dhand told CNBC that "There are radical groups in the main square which will not give up until Yanukovych resigns." She said there was still hope for negotiations between the government and the opposition, but that the latter needed to get a better rein on the disparate anti-Yanukoych groups.
(Read more: Obama warns of consequences as Ukraine battle rages)
Sanctions against Ukraine have also been suggested from European circles, most notably from German Chancellor Angela Merkel, in an effort to quell government forces, although Russian Foreign Minister Sergey Lavrov said that such a threat was akin to blackmail.
In televized remarks, Russian Prime Minister Dmitry Medvedev suggested that more of a crackdown was needed from the administration in Kiev. "We need partners who are in good shape and for the authorities that work in Ukraine to be legitimate and effective, so that people don't wipe their feet on them likea doormat," he said.
In the Olympic village in Sochi, some Ukrainian athletes added black armbands to the Ukrainian flags hanging from their balconies after Olympic officials told them they were not allowed to wear the armbands in competition.
Some members of Ukraine's Olympics team have decided to leave the Winter Games.
—By CNBC's Kiran Moodley. Follow him on Twitter
Reuters contributed to this article.