The EU has suspended its trade talks with Ukraine, disappointing the tens of thousands of demonstrators there who are demanding closer ties with the West.
The US Senator and former Presidential candidate John McCain addressed the crowds today, telling them their "destiny lies in Europe."
Harry Smith reports:
US Senators John McCain and Christopher Murphy told journalists on Sunday that Ukraine faced "a clear choice between its past and future", voicing their support for pro-EU protesters who have been out in the streets for the third week in a row demanding a European future for their country.
Speaking to journalists after addressing crowds, both senators said Russia's interference in Ukrainian matters was not welcome, adding that it was disturbing to hear that the EU may be suspending talks with Ukraine on the trade and political agreement.
US Senator John McCain told thousands of Ukrainian protesters camped on Kiev's main square on Sunday that Ukraine's destiny lay in Europe and that it would make Europe better.
Senators John McCain and Christopher Murphy both addressed the crowd from a stage.
"We are here to tell you that the American people and the United States Congress stands with the people of Ukraine," Murphy told the crowd.
"The way towards change goes through peaceful protest. And in America we stand in awe of the fact that despite the violence on the square you have remained peaceful in support of change," he added.
United States Senator John McCain has told protesters rallying for Ukraine's integration within the European Union that "Ukraine will make Europe better and Europe will make Ukraine better".
"We are here to support your just cause, the sovereign right of Ukraine to determine its own destiny freely and independently," Senator McCain said.
"The destiny you seek lies in Europe."
Supporters of Ukrainian President Viktor Yanukovych have rallied in central Kiev, waving flags and displaying placards of the their leader's political party, the Party of Regions.
The European Union says it is putting on hold work with Ukraine on a trade agreement, saying Ukraine government arguments have "no grounds in reality".
EU enlargement chief Stefan Fuel tweeted that he had told Ukraine's first deputy prime minister Serhiy Arbuzov last week that further discussion on the trade agreement was conditional on a "clear commitment" by Kiev to sign. However, Mr Fuel said he had not heard back from the Ukraine government.
Ukraine president Viktor Yanukovych previously rejected a deal with the EU, leading to weeks of demonstrations.
The trade deal was set to strengthen ties between Ukraine and the EU.
Pro-European integration protesters remain barricaded in Independence Square in Kiev after US Senator John McCain met with Ukrainian opposition leaders yesterday, voicing his support for the demonstrations.
US Senator John McCain is in Ukraine to meet members of the opposition and government as efforts to mediate the political crisis in the country continue.
Senator McCain said he was clear that he saw the future of Ukraine inside Europe.
Further protests have been called by both sides tomorrow. Today tens of thousands attended rival rallies in the centre of Kiev.
US Senator John McCain met with the leaders of the Ukrainian opposition tonight in Kiev.
Senator McCain had talks with Vitaly Klitschko, Arseniy Yatsenyuk and Oleh Tyahnibok to "reiterate" the US's "commitment to a peaceful resolution" following large protests.
He called for the democratic right to protest peacefully to be respected. He said:
"Ukraine is a western, a European nation and of course none of us want any violence. These are peaceful demonstrations and we argue strongly that no violence should be imposed by anyone. This is their democratic right."
Democrats and Republicans have condemned the Ukrainian government's measures during weeks of protests by hundreds of thousands of people over President Viktor Yanukovich's decision to scrap a trade deal with the European Union and steer Ukraine closer to Russia.
Tens of thousands of Ukrainians rallied in support of President Viktor Yanukovich in central Kiev today, separated by a line of riot police from anti-government protesters who have camped out for weeks in a nearby square.
A day after talks between the government and the opposition failed to resolve the political crisis, Yanukovich's supporters waved the blue flags of his Party of Regions and chanted the president's name.