Ukraine violence: US considers sanctions
The US state department has said it is considering all options, including sanctions, towards Ukraine as the political crisis there continues.
It follows attempts by riot police to dislodge anti-government protesters from their strongholds in the capital.
The US warned Ukraine not to use its armed forces against civilians.
US officials say the Ukrainian Defence Minister Pavlo Lebedyev said his government would not use the army against the protesters.
Mr Lebedyev was speaking in a telephone call to US Defence Minister Chuck Hagel, who underlined the potential damage of any involvement by the military in breaking up the demonstrations, according to a US spokesperson.
The weeks of demonstrations in the centre of Kiev have paralysed the country of 46 million people.
Both EU foreign policy chief Catherine Ashton and US Assistant Secretary of State Victoria Nuland were in Kiev on Wednesday and met protesters as well as members of President Viktor Yanukovych's government.
With each attempt to solve the problem posed by the Ukrainian "Euromaidan" demonstrators, President Viktor Yanukovych seems to dig himself into an even bigger political hole.
Interior ministry officials said the reason why scores of riot police swept into the Independence Square protest camp was to "clear the street" for traffic. To many observers it seemed that the overwhelming show of force was instead an attempt to drive out the protesters once and for all.
Whatever the reason, the mass civil disobedience movement, which was sparked when Mr Yanukovych unexpectedly decided to put on hold an historic trade agreement with the EU, has received yet another major boost.
Protesters on Wednesday were inspired and defiant as they stood in Independence Square and recounted how they had turned back the police with an impregnable human wall, and, at the mayor's office, with water hoses and barricades.
The elite Berkut riot police have since retreated, as if to lick their wounds. And protest organisers are promising an even bigger rally this weekend than even last Sunday's historic gathering. But so far, neither gigantic demonstrations, nor attempts to force the protesters out have broken the political deadlock.
"We are considering policy options... sanctions are included but I am not going to outline specifics," said state department spokesperson Jen Psaki.
"There is a range of options that we are open to, but we are not at that point at this stage."
Earlier, US Secretary of State John Kerry expressed "disgust" at the decision by Ukraine's authorities to "meet the peaceful protest... with riot police, bulldozers, and batons, rather than with respect for democratic rights and human dignity".
Police moved in on the main protest camp in Independence Square in the early hours of Wednesday. They dismantled some barriers and tents saying they were trying to free up a passage through the square for traffic.
Protesters in hard hats locked arms to form human walls to try to resist the police push. At least nine people were detained and there were some reports of police using violence.
Eventually the police pulled back from both Independence Square and city hall, where they made an abortive attempt to oust occupying protesters.
President Viktor Yanukovych again invited all parties, including the opposition, for talks on resolving the political crisis.
"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," the president said in a statement published on his website.
He added that the authorities would "never use force against peaceful protests".
But the opposition were scathing. "Instead of a round table, what we got is a break-up [with] truncheons," said opposition leader Oleksandr Turchynov. "The authorities are driving into a dead end."
Tensions have been high since the government last month refused to sign a deal on closer ties with the European Union.
The U-turn followed pressure from Russia, which has said Ukraine's free trade deal with the EU would flood the Russian market.
Prime Minister Mykola Azarov on Wednesday said Ukraine wanted 20bn euros ($28bn; £17bn) in aid from the EU in return for signing the agreement.