Top Western diplomats are visiting Kiev as police move to break the blockade of Ukrainian government buildings by pro-EU protesters.
US Deputy Secretary of State Victoria Nuland met leading opposition politicians and was due to have talks with President Viktor Yanukovych.
The Ukrainian leader met EU foreign policy chief Catherine Ashton.
He has announced the government is resuming talks on the EU association agreement at the heart of the unrest.
By suspending negotiations just before the deal was due to be signed at an EU summit last month, Mr Yanukovych plunged Ukraine into uncertainty.
However, Mr Yanukovych appears to have again stressed the need to strengthen economic ties with Russia, which strongly opposes the EU agreement.
Several people were hurt overnight as riot police advanced on protesters.
But no action was taken against the main opposition camp on Independence Square, where about 2,000 protesters remained on Tuesday morning, huddling around braziers to keep warm, Reuters news agency reports.
On Sunday, at least 100,000 protesters turned out, demanding the resignation of the government within 48 hours
There were no immediate details of Baroness Ashton’s talks with Mr Yanukovych but, speaking before the visit, she voiced concern about a police raid on the headquarters of Ukraine’s biggest opposition party, Fatherland.
Computer servers were removed during the raid on the party led by former Prime Minister Yulia Tymoshenko, who has been in prison since 2011 over a controversial gas contract with Russia.
“I follow with concern the reports that police forces forcibly entered the office of the biggest opposition party,” Baroness Ashton said in astatement.
T, has said the EU could “step up” financial aid to Ukraine but rejected “speculation” about the cost of upgrading Ukraine’s economy under the association agreement.
In a speech to the European Parliament, the EU’s enlargement commissioner, Stefan Fuele said the EU was ready to help Ukraine financially “including through topping up IMF loans with macro-financial assistance [and] stepping up the European Union’s financial assistance programmes”, but it was not clear whether this was an increase over previous offers.
Mr Yanukovych has complained of the cost of upgrading Ukraine’s economy to EU standards, saying 20bn euros (£16.7bn; $27.4) a year would be needed while the EU offered only a fraction of that sum.
Ms Nuland met Vitaly Klitschko, the heavyweight boxing champion who leads the Udar (Punch) party, as well as Arseniy Yatsenyuk, of Tymoshenko’s Fatherland party, and Oleh Tyahnybok, of the far-right Svoboda party.
In Moscow earlier, the US diplomat expressed “deep concern” about events in Ukraine, stressing Washington’s support for Ukrainians’ “European choice”.
She “urged Russia to use its influence to press for peace, human dignity and a political solution”, the US embassy in Moscow said in a statement.
Mr Yanukovych discussed the crisis at a televised round table on Tuesday with his three predecessors as president of Ukraine – Leonid Kravchuk, Leonid Kuchma and Viktor Yushchenko. No representatives of the street demonstrators were present.
President Yanukovych said a working group led by a deputy prime minister would “probably” go to Brussels on Wednesday to resume work with the European Commission on the association agreement.
“We cannot talk about the future without talking about restoring trade relations with Russia,” he added, quoted by Reuters news agency.
He said he had asked the prosecutor general to ensure the release of some protesters detained last month – those who had not committed grave crimes and who had children or families.
“Certainly, such people will be released,” he said.
The street protests, the biggest since 2004, have invited parallels with that time. On each of the last three Sundays, crowds estimated at 100,000 or more have flooded central Kiev.
On Monday, phalanxes of riot police, their helmets caked in snow, moved to clear Kiev’s government district of protesters, tearing down barricades leading to the presidency, cabinet offices and parliament.
Scuffles broke out and, while there were no immediate official reports of injuries, members of Svoboda said several people had been hurt. Two police officers were also reportedly injured.
The unrest in Kiev and other parts of Ukraine escalated after police used violence against protesters on 30 November.
The crisis has highlighted divisions in Ukraine, with many in the east of the country more sympathetic to Russia, and opposing both closer links with the EU and the anti-government protests.