KIEV, Ukraine — A top opposition leader on Thursday urged protesters to maintain a shaky cease-fire with police after at least two demonstrators were killed in clashes this week, but some in the crowd appeared defiant, jeering and chanting ‘‘revolution’’ and ‘‘shame.’’
Emerging from hours-long talks with President Viktor Yanukovych, opposition leader Oleh Tyahnybok asked demonstrators for several more days of a truce, saying the president has agreed to ensure the release of dozens of detained protesters and stop further detentions.
But other opposition leaders offered mixed reports on the outcome of the meeting, with Vitali Klitschko saying negotiations had brought little result.
He and Tyanhnybok were booed by angry demonstrators.
‘‘We are not going to sit and wait for nobody-knows-what,’’ said protester Andriy Pilkevich, who was building barricades from giant bags of ice while wearing a ski mask. ‘‘Those who want to win must fight.’’
Interior Minister Vitali Zakharchenko issued a statement guaranteeing that police would not take action against the large protest camp on Independence Square, known as the Maidan. He also called on police to exercise calm.
The developments came as hundreds of enraged protesters in several regions in western Ukraine, where Yanukvoych has little support, seized government offices and forced one governor loyal to Yanukovych to resign.
At least two people were killed by gunfire at the site of clashes in Kiev on Wednesday. Demonstrators had pelted riot police with stones and set police buses on fire. Officers responded with rubber bullets, tear gas, and stun grenades.
Opposition leaders had offered a Thursday evening deadline for the government to make concessions or face renewed clashes.
Although one opposition leader, Arseniy Yatsenyuk, said after the talks that ‘‘there is a really good chance’’ to stop the bloodshed, Klitschko was more downbeat. ‘‘The only thing we were able to achieve was not much,’’ he told the crowd.
He urged protesters to avoid further bloodshed.
‘‘I am afraid, yes, I am afraid of human losses,’’ Klitschko said. ‘‘We will be widening the territory of the Maidan further until these guys start reckoning with us.
The president called a special session of Parliament next week to discuss the tensions, telling the Parliament speaker: ‘‘The situation demands an urgent settlement.’’ But there was no indication the move represented a compromise.
Protests began after Yanukovych turned away from closer ties with the European Union in favor of getting a bailout loan from Russia. They turned violent this week after he pushed through harsh anti-protest laws, rejecting protesters’ demands that he resign.
Support for Yanukovych is very thin in western Ukraine, and most residents want closer ties to the 28-nation EU.
In Lviv, 280 miles west of Kiev, hundreds of activists burst into the office of regional governor Oleh Salo, a Yanukovych appointee, shouting ‘‘Revolution!’’ After forcing him to sign a resignation letter, an activist ripped it out of Salo’s hands and lifted it up to cheers. Salo later retracted his signature.
Meanwhile, hundreds of protesters smashed windows, broke doors, and stormed into the governor’s office in the city of Rivne, shouting ‘‘Down with the gang!’’ — a common reference to Yanukovych’s government.
Angry crowds also besieged government offices in other western regions.
Anger spread after a video was released online appearing to show police abusing a naked protester.
In the video, a young man is made to stand in the snow in freezing temperatures, while a policeman punches him in the head and others force him to pose for photos.
The Interior Ministry issued a statement, apologizing ‘‘for the impermissible actions of people wearing police uniforms’’ and launched an investigation.