* Pro-Russia separatists not about to quit sit-ins
* Geneva agreement commits to ending occupations
* Russian speakers want Kiev nationalist camp cleared (Adds further comment, background)
By Gabriela Baczynska and Aleksandar Vasovic
DONETSK, Ukraine, April 17 (Reuters) - Pro-Russian separatists occupying public buildings in eastern Ukraine reacted to an international accord to defuse the crisis on Thursday by saying they would not agree to leave the sites before other major conditions were met.
The Ukrainian and Russian governments, along with the United States and European Union, signed an agreement in Geneva that said: "All illegal armed groups must be disarmed; all illegally seized buildings must be returned to legitimate owners; all illegally occupied streets, squares and other public places in Ukrainian cities and towns must be vacated."
Pro-Russian activists in Donetsk, the biggest city in the Russian-speaking, industrial east, said that wording meant Ukrainian nationalists still camped out on Kiev's Maidan two months after their protests overthrew the Kremlin-backed president must also clear away their barricades.
One protest leader even interpreted the Geneva deal to mean that the prime minister and acting president must step down -since they were illegally "occupying" the offices of state.
Other activists said they planned to maintain their sit-ins until they could hold a referendum next month that some believe can emulate Crimea and see the region annexed to Russia.
That risks a continuation of a sometimes violent stand-off, which the four parties in Geneva agreed would start being defused in the coming days under the auspices of monitors from the Organisation for Security and Cooperation in Europe (OSCE).
"If it means all squares and public buildings, then I guess it should start with the Maidan in Kiev," said Alexander Zakharchenko, leader of a group of martial arts athletes who are among those occupying a local government building in Donetsk. "We'll see what they do there before we make our decision here."
Also there, Kirill Rudenko, a spokesman for the self-declared People's Republic of Donetsk, said Prime Minister Arseny Yatseniuk and acting president Oleksander Turchinov "must liberate the buildings they are occupying and give up their posts": "Only then will we discuss what to do here in Donetsk."
The current authorities in Kiev took power when President Viktor Yanukovich fled to Russia in February after police killed dozens of protesters on Independence Square, known as Maidan.
The area is still ringed by barricades. Activists camped out there - including far-right nationalists denounced as "fascists" by Moscow and by many Russian speakers in eastern Ukraine - have said they will only leave if they are satisfied by the results of a presidential election called for May 25.
Unlike in eastern Ukraine, protesters on Maidan do not as a rule carry firearms. But they held out against deadly gunfire in February and remain suspicious of the leaders now exercising power in parliament. That poses a problem for the government if it tries to enforce a clear-out in the centre of the capital.
Despite accusations from Kiev and the West, Russia denies any hand in the takeover of public buildings in eastern Ukraine begun last week, and so can argue it is not in a position to make activists leave. It has, however, warned it might step in to protect protesters from attacks by Ukrainian authorities.
Kiev said its forces killed three militants overnight when a crowd tried to take over a military base. But it has not stormed occupied buildings and the Geneva agreement binds all sides to "refrain from violence, intimidation or provocative actions".
In Donetsk, Yevgeny, a masked separatist manning a barricade in front of the regional government building, said : "If our leaders tell us to leave, we will leave. But our demands remain - we want a regional referendum on May 11.
"We will not hand over our weapons."
His comrade, Sasha, said: "We've shown those fascists in Kiev they cannot oppress us. We will have our Donetsk republic."
The Geneva agreement commits the Kiev government to a national dialogue and it has promised to devolve more powers to the regions and protect the rights of Russian-speakers. But it opposes the kind of local referendums and federal autonomy for regions it says would lead to the break up of the country.
Nikolai Solntsev, a leader in the Donetsk People's Republic, said of the Geneva pact: "It's all just a diplomatic trick. No one is leaving here before the referendum planned for May 11." (Additional reporting by Thomas Grove in Slaviansk; Writing by Alastair Macdonald; Editing by Hugh Lawson)