Pro-EU demonstrators in Ukraine have dug in as the United States warned of possible sanctions over Kiev's crackdown on opposition protests, urging authorities to show restraint.
The demonstrators - who have occupied the capital's Independence Square in anger at the rejection of a landmark European Union pact - forced riot police to retreat following a pre-dawn raid on Wednesday on their protest camp in a blow to the authority of President Viktor Yanukovych.
International pressure is mounting on the embattled leader, with EU foreign policy chief Catherine Ashton meeting him twice in recent days and US Assistant Secretary of State Victoria Nuland telling the president the attempted police crackdown was "inadmissible".
About 30 people were injured when riot police and interior ministry special forces moved against the demonstrators.
But just hours later Yanukovych vowed authorities would never use force against peaceful protests and urged the opposition to sit down for talks.
"For the sake of achieving compromise I am calling on the opposition not to reject (talks), not to follow the path of confrontation and ultimatums," Yanukovych said in a statement.
"I am ready to participate in such round-table talks personally."
The United States said on Thursday it was considering a range of options in response to the crackdown, including possible sanctions.
"We are considering policy options. There obviously has not been a decision made. Sanctions are included, but I am not going to outline specifics," State Department spokeswoman Jen Psaki said.
Pentagon chief Chuck Hagel warned the Ukrainian authorities against using military force on demonstrators "in any fashion," and urged restraint.
In a call with his Ukrainian counterpart Pavlo Lebedev, Hagel "underlined the potential damage of any involvement by the military in breaking up the demonstrations," assistant Pentagon spokesman Carl Woog said in a statement.
Earlier, security forces tore down makeshift barricades in Independence Square but were eventually forced into a humiliating retreat amid cheers from the demonstrators after the ranks of protesters swelled.
City authorities said 30 people sought medical help and half of them were hospitalised.
"We have not won the war yet, but we've decisively won this battle. The authorities are panicking," said protester Anton Kulyk.
The opposition, which has previously ruled out any negotiations until Yanukovych dismisses the government and punishes riot police for crushing a smaller protest on November 30, vowed to do everything to topple the president.
Jailed former prime minister Yulia Tymoshenko warned the protest movement against holding any negotiations with Yanukovych.
"I am calling on all Ukrainians: rise up!" Yanukovych's arch rival said in a statement on Wednesday. "No talks with the gang."
The early morning police action - which came as both Nuland and Ashton were in Kiev - sparked unprecedented international criticism of Yanukovych, with US Secretary of State John Kerry expressing "disgust" at the crackdown.
An estimated 5000 pro-EU demonstrators were camping out in Independence Square on Wednesday night, reinforcing barricades with snow and sand bags.
The spiralling crisis risks pitting the Ukrainian-speaking, pro-EU west of the country against the Russian-speaking, largely pro-Yanukovych east.
Wednesday's police crackdown came just hours after three former Ukrainian presidents - Leonid Kuchma, Leonid Kravchuk and Viktor Yushchenko - called on Yanukovych to protect the rights of protesters.
