The US Vice-President, Joe Biden, landed in Kiev on Monday for a two-day visit aimed at showing American support for the new Ukrainian government and to push for implementation of a diplomatic accord reached in Geneva last week between Ukraine, the US, the European Union and Russia to de-escalate tensions.
Days after the supposed breakthrough was reached, with putative backing from Moscow, there is still little sign of it actually having any effect on the ground in eastern Ukraine, where Russian-speaking militants have ignored calls to lay down their arms and give up buildings they have been occupying in several cities.
Even as Mr Biden was leaving Washington on Sunday, violence reached a new level after a shootout erupted at a checkpoint manned by pro-Russian insurgents near the eastern town of Slovyansk. It left three people dead and triggered a new round of recriminations between Kiev and Moscow.
While the Ukraine government said it was the fault of provocateurs from outside the country, the Russian foreign ministry placed the blame on so-called Ukrainian nationalists. In a statement, the Russian Foreign Minister, Sergei Lavrov, who attended the Geneva talks, accused Kiev of a " crude violation of the agreements" reached.
"Steps are being taken - above all by those who seized power in Kiev - not only that do not fulfil, but that crudely violate the Geneva agreement," he said. "The authorities are doing nothing, not even lifting a finger, to address the causes behind this deep internal crisis in Ukraine."
Mr Lavrov also said it was "absolutely unacceptable" that Ukrainian authorities had failed to remove what he labelled illegal protests from squares in Kiev.
In a separate move, the Kremlin said President Vladimir Putin has approved legal amendments to make it simpler for Russian speakers in former Soviet countries to acquire Russian citizenship.
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Washington will decide within the next few days whether the apparent faltering of the Geneva accord, which called for a laying down of arms in zones of tension and the start of a national dialogue on constitutional reform, warrants further sanctions against Moscow, aimed at people in Mr Putin's inner circle and possibly business entities tied to Russia's energy and defence sectors.
After his arrival, Mr Biden was expected to embark on a series of meetings in Kiev, notably with Arseniy Yatsenyuk and Oleksandr Turchynov, the acting Prime Minister and President, respectively. Officials travelling with the Vice-President told reporters that Mr Biden would announce new technical assistance to help Ukraine reduce its energy dependence on Russia, and to tap natural gas supplies from European neighbours. He was also set to discuss additional, non-lethal military assistance.
Mr Biden is the highest-level US official to visit Ukraine since the crisis erupted. An official in his entourage said he "wanted to come to Kiev to send a very clear message of US support for Ukraine's democracy, unity, sovereignty and territorial integrity".
He added: "[Mr Biden] will call for urgent implementation of the agreement reached in Geneva last week while also making clear ... that there will be mounting costs for Russia if they choose a destabilising rather than constructive course in the days ahead."
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