* Protesters moved into City Hall in early December
* They expect criminal charges dropped against activists
* New anti-government rally called for Sunday in Kiev
By Richard Balmforth
KIEV, Feb 16 (Reuters) - Scores of Ukrainian anti-government protesters ended a two-month-old occupation of city hall in the capital Kiev on Sunday to meet a government amnesty offer.
Demonstrators had swept into the main municipal building in early December as a popular revolt mushroomed against President Viktor Yanukovich's decision to ditch a trade pact with the European Union in favour of cultivating close economic ties with Russia, Ukraine's former Soviet master.
Under an amnesty arrangement aimed at defusing the crisis, Ukrainian authorities have offered to drop all criminal charges against activists who have been provisionally freed as long as municipal buildings are cleared of protesters and some main roads unblocked by Monday.
Masked men in military fatigues and the demonstrators they had protected against riot police since mid-December filed out of Kiev city hall on Sunday but they threatened to return if authorities did not carry out the amnesty promise.
Opposition deputies said protesters had similarly pulled out of municipal buildings in several areas of western Ukraine, a hotbed of opposition to Yanukovich, and in one part of the southeast where the president has retained more support.
"We are doing all we can so that the amnesty law will be able to enter into force. There was a decision made to free the building of the Kiev Council (City Hall) and we are doing that. There will not be a single protester left there," said Oleh Helevey, a deputy for the far-right nationalist party Svoboda.
"But if the prosecutor's office does not declare that the law has come into force, we reserve for ourselves the right to occupy administrative buildings again," he said.
Opposition sources said protesters had also agreed to ease blockages of traffic on a through road leading to government headquarters and parliament that was the flashpoint in January of violent clashes between riot police and radical activists.
But they said barricades would largely remain in place.
Another large-scale opposition rally was scheduled on Sunday in Kiev's Independence Square, focal point of the rebellion against Yanukovich's leadership.
The unrest was sparked last November by Yanukovich when he spurned a free trade agreement long in the making with the European Union and opted for a $15 billion package of Russian credits and cheaper gas to help Ukraine's ailing economy.
At least six people have been killed in the unrest.
Andriy, commander of about 100 men in black balaclavas who filed out of City Hall, said the building was being cleared on the understanding that charges would be dropped against activists who had been earlier detained by police.
Asked what he and his men would do if the authorities did not fulfil their promise, he replied: "Then we'll come back."
(Editing by Mark Heinrich)