Ukraine PM Mykola Azarov warns of coup in making
Ukraine's PM says he sees "all the signs of a coup" as protests intensify.
Mykola Azarov said the government was aware of plans to seize the parliament building in the capital Kiev.
Demonstrators are blockading the main government building, continuing protests against a decision not to sign a deal for closer ties with the EU.
President Viktor Yanukovych has called for only peaceful rallies after violence during a weekend of protests which saw many injured.
In another development on Monday, Mr Yanukovych asked the European Commission to allow him to send a delegation for talks on "some aspects" of the EU association agreement that Ukraine had been expected to sign, officials in Brussels said.
EC President Jose Manuel Barroso agreed to the request but stressed the Commission was ready to discuss implementation of accords already initialled, "but not to re-open any kind of negotiations".
Opposition leaders have renewed demands that Mr Yanukovych stand down, and urged him to "stop political repression".
The protests began just over a week ago after a halt was ordered to preparations to sign a deal on closer integration with Europe.
"Out with the gang!"
Hundreds of people put up tents on Independence Square on Sunday night, after a mass rally that drew hundreds of thousands, amid calls for a general strike.
The headquarters of the cabinet has been blockaded, with government employees unable to reach work.
Police reinforcements are being sent to Kiev, the newspaper Ukrainska Pravda reported.
As thousands of protesters converged on Independence Square on Monday, they chanted slogans including "Out with the gang!"
Prime Minister Mykola Azarov, quoted by Interfax news agency, said the political opposition in Ukraine had the "illusion" that it could overthrow the existing order.
"We know that a plan is being prepared to seize the parliament," he said.
Speaking during a meeting, Mr Azarov told Western ambassadors on Monday: "This has all the signs of a coup...
"That is very serious. We are patient, but we want our partners not to feel that everything is permitted."
Later on Monday, the US weighed in to dispute Mr Azarov's interpretation.
"We certainly don't consider peaceful demonstrations coup attempts," a White House spokesman said.
Jay Carney added that while violence by the authorities against demonstrators on Saturday had been "unacceptable", the police had in general been more restrained since.
Parliament is due on Tuesday to discuss the possibility of holding a vote of no confidence in Mr Azarov's government.
For his part, President Yanukovych urged police and demonstrators to observe the law.
"Any bad peace is better than a good war," Mr Yanukovych said in a TV interview reported by his own website - his first comments on Sunday's violence.
President Vladimir Putin of neighbouring Russia said events in Ukraine seemed "more like a rampage than a revolution."
Mr Putin blamed "outside actors" for the protests, which he said were an attempt to unsettle Ukraine's "legitimate" rulers.
On Sunday, several hundred thousand people took part in a march, defying a ban on rallies.
There were clashes near the presidential building, with demonstrators firing flares and riot police using tear gas, batons and stun grenades. TV footage appeared to show officers beating reporters.
The main opposition leaders condemned the violence, saying it was the work of "provocateurs". There were also clashes on Sunday as Kiev protesters tried to topple a statue of Lenin.
On Saturday, police violently dispersed an opposition camp.