KIEV: Hundreds of angry demonstrators issued an ultimatum to the Ukrainian government on Sunday, demanding amnesty for fellow activists just hours after vacating city hall, the epicentre of a winter of protests.
"We are issuing an ultimatum to authorities -- if they do not immediately announce the complete and unconditional rehabilitation (of protesters) in some 2,000 cases, we will retake city hall," Andriy Illenko, a lawmaker from the nationalist opposition Svoboda (Freedom) party, told protesters.
"This ultimatum expires in several hours," he warned, as around 500 protesters gathered in front of city hall, some wearing helmets and army jackets, hitting metal batons on the ground.
They had occupied the building since December as part of a movement that has rocked Ukraine for nearly three months over President Viktor Yanukovych's decision to ditch a key EU trade pact in favour of closer ties with Russia.
But in a conciliatory gesture early Sunday, up to 700 protesters evacuated the building in response to a last-minute concession by the authorities who released all protesters detained in unrest on Friday.
City hall was eerily quiet inside, with many of the protesters' drawings and photos still on the walls.
The evacuation of city hall was one of the conditions set in an amnesty law approved by Yanukovych early this month, promising to heed opposition demands to release detainees and drop charges against them.
Some protesters -- including at least one disabled man and a retiree -- have been charged with fomenting mass unrest, which carries a sentence of up to 15 years in jail.
In Brussels on Sunday, EU foreign policy chief Catherine Ashton hailed the release of the detainees but called on Kiev to drop all pending court cases against protesters.
"I expect such action to be taken without delay so as to facilitate the political dialogue in (Ukraine's) parliament this week," she said.
On Friday, just as negotiations between the warring parties had ground to a standstill, authorities unexpectedly announced they had freed all 234 people detained in the protest movement, prompting the evacuation in exchange.
But many taking part in a mass rally on Sunday near city hall were unhappy with the decision.
"It's a bad decision... We can't trust the authorities, they're crooks. The opposition is making a big mistake," said Volodymyr Penkivski, a 56-year-old protester who had come from northern Ukraine.
"Yanukovych will take other (protesters) hostage. We can't beat a retreat. Otherwise we will all go to prison."
Speaking at the rally on Independence Square, Arseniy Yatsenyuk, an opposition leader, said that unless all charges against protesters are dropped, "we will launch a peaceful offensive." He did not elaborate.
The opposition has also agreed to vacate part of Grushevsky Street, where deadly riots took place in late January, to allow traffic to move freely.
On Sunday, an opening had been carved out in one of the street's barricades, but this was fiercely guarded by a row of protesters in combat gear.
Nearby, opportunistic vendors sold calendars and magnets depicting scenes of the months-long protest.
The opposition still has a host of unmet demands, including a major reform of the constitution to reduce presidential powers in favour of the government and parliament.
Protesters are still occupying several other public buildings in Kiev, as well as Independence Square, which has become a sprawling anti-government tent city protected on all sides by manned barricades.
The 600 to 700 Ukrainians who had camped out in city hall have since moved to the October Palace, a stately concert hall that has been under occupation for several months.
Ultimately, protesters want Yanukovych himself to leave.
Andreas Umland, a political scientist at Kyiv-Mohyla Academy in the Ukrainian capital, said the government and opposition were thought to be negotiating a form of power-sharing to be implemented before early presidential elections are held.
"For now the main question is whether Yanukovych will agree to power-sharing, what kind of power-sharing and how much power will be left to the office of the president," he said.