KIEV, Ukraine — Ukrainian President Viktor Yanukovich said he would meet with his three predecessors Tuesday in an effort to resolve a political crisis that escalated with the storming of an opposition party headquarters by armed riot police.

Yanukovich announced plans Monday for what he said would be a nationally televised round-table discussion with the other three men who have served as president of Ukraine since it broke away from the Soviet Union in 1991. Yanukovich was also expected to meet with European Union envoy Catherine Ashton, who is reportedly planning to talk to both sides in Kiev, the capital, on Tuesday.

The capital has been rocked by massive demonstrations in recent weeks after Yanukovich’s decision to reject a proposed trade pact with the EU. By default, that leaves Russia as Ukraine’s leading economic ally, angering Yanukovich’s Western-leaning opponents.

The demonstrations continued peacefully Monday, but there were moments of tension. Throughout the day, riot police were dismantling barricades and tents erected by protesters around government buildings. The demonstrators did not resist the clearance, but promised to rebuild on Tuesday.

Late Monday, riot police armed with Kalashnikov rifles stormed the central Kiev headquarters of the Batkivshchyna party, led by former Prime Minister Yulia Tymoshenko. Tymoshenko, who is in prison for abuse of power, has been urging her followers to seek the ouster of Yanukovich.

“They are breaking doors, furniture, seizing computers and other things,” Tymoshenko’s press secretary, Marina Soroka, said in a telephone interview during the raid.

She later said that the police had spent about an hour and a half in the party’s offices, making no arrests but ransacking the premises and taking away computer servers and other equipment that belong to the party and three affiliated media organizations. The Interior Ministry confirmed that account.

It was not clear whether the raid was directly related to the political confrontation. The Interior Ministry said police were searching the Batkivshchyna offices as part of an investigation into a fraud and abuse-of-office case.

Opposition leader and Tymoshenko deputy Arseny Yatsenyuk denounced the raid. “If President Yanukovich thinks that he can resolve the political and economic crisis in the country with the help of interior troops and … riot police, he is making a mistake,” he said.

But Prosecutor General Viktor Pshonka sternly warned the opposition against “arrogantly violating the law.”

“I am once again addressing all those involved in mass disorders: Don’t test the patience of the authorities, don’t provoke law enforcement organs,” Pshonka said in a statement published on his agency’s website. “Should somebody think that by such actions anarchy and lawlessness can be installed in the country, you should drop your illusions! There is power and law at work in the state.”

Ashton’s planned visit on behalf of the EU was a sign of international concern about the situation in Ukraine, as was a phone call to Yanukovich from Vice President Joe Biden.