Denis Pushilin of the self-appointed Donetsk People's Republic told reporters the insurgents in more than 10 cities do not recognize Ukraine's interim government as legitimate and will not leave the buildings until the government resigns. He demanded that Ukrainian leaders abandon their own public buildings.
Talks between Ukraine, Russia, the United States and the European Union produced an agreement Thursday in Geneva to take tentative steps toward calming tensions in Ukraine. The country's former leader fled to Russia in February and Russia annexed Crimea in March. The Geneva agreement calls for disarming all paramilitary groups and immediately returning all government buildings seized across the country.
Pushilin, speaking at the insurgent-occupied regional headquarters in the eastern city of Donetsk, said the agreement was "reasonable" but insisted "everyone should vacate the buildings," including Arseniy Yatsenyuk and Oleksandr Turchynov, the acting Ukrainian prime minister and president.
Ukraine has scheduled a presidential election for May 25, but Pushilin reiterated a call to hold a referendum on self-determination for the Donetsk region by May 11. The same kind of referendum in Crimea led to its annexation by Russia.
Ukraine has faced months of turmoil, first in Kiev by protesters angry that former President Viktor Yanukovych wanted closer ties with Russia instead of Europe, then in eastern Ukraine by pro-Russian supporters. Now many of the buildings in the east occupied by the tacitly Moscow-supported insurgents are in the hands of highly trained gunmen — a situation that has complicated authorities' plans to retake them.
Pushilin said the insurgents would not hand over their weapons until the government halts efforts to reclaim the occupied buildings.
"As far disarmament goes, the Kiev junta has already begun violating its agreements since yesterday, by announcing that it will not pull its troops out of Slovyansk and Kramatorsk," Pushilin said, referring to two cities occupied by the insurgency.
In a sign that Ukraine's fledging government is ready to meet some of the protesters' demands, the acting president and prime minister issued a joint statement Friday saying the Ukrainian government is "ready to conduct a comprehensive constitutional reform that will secure powers of the regions," giving them a greater say in local governance.
They also pledged "a special status to the Russian language" and vowed to protect the rights of all citizens whatever language they spoke.
Yatsenyuk also told parliament Friday the government has drafted a law to offer amnesty to all those willing to lay down their arms and leave the occupied government buildings.
Russia says Ukraine's interim government is illegitimate but has not said its leaders should vacate their offices.
Kiev-based political analyst Vadim Karasyov said Ukraine's fledgling government does not have the resources to resolve the standoff in eastern Ukraine militarily, so it's going to have to negotiate with the pro-Russian protesters.
Kiev "should finally listen to the demands of those people," he said. "They don't even know what their demands are. Maybe they are reasonable. The government in Kiev is pretending that there are no problems in the east."
In Washington, President Barack Obama conveyed skepticism about Russian promises to de-escalate the volatile situation in Ukraine, and said the United States and its allies were ready to impose more sanctions if Moscow doesn't make good on its commitments.
Russian President Vladimir Putin's spokesman, Dmitry Peskov, complained on state television about possible further sanctions against Russia.
"You must not act toward Russia as if it were a naughty schoolgirl, to whom you thrust some kind of paper where it's necessary to mark off that she did her homework," Peskov said.
Meanwhile, former Ukrainian prime minister and presidential hopeful Yulia Tymoshenko arrived Friday in Donetsk in a bid to defuse the tensions and hear "the demands of Ukrainians who live in Donetsk."
"I'd like to listen to these demands by myself and find out how serious they are, so that one could find the necessary compromise between the east and the west that will allow us to unite the country," she told The Associated Press.
Russian Foreign Minister Sergey Lavrov has emphasized that the requirement to abandon occupied buildings applied to all parties — an apparent reference to the ultranationalist Right Sector, whose activists are occupying Kiev city hall and a Kiev cultural center.
Russia's Foreign Ministry repeated that notion Friday, saying in a statement "it's obvious that when we talk about disarmament, we have in sight first of all the removal of weapons from the fighters of Right Sector and other pro-fascist groups participating in the February overthrow in Kiev."
In Donetsk, the barricade-lined space in front of the regional administration building, a mustering point for pro-Russian supporters, was nearly empty Friday despite warm weather. Patriotic Soviet-era music blared over loudspeakers.
One man in the square, 56-year-old militia member Igor Samoilov, said he would not support pulling back from any seized buildings.
"Russia can play these games with the West, but we will not," Samoilov said.
Sitting nearby, 86-year-old Yuri Kovalchuk said Moscow needed to intervene directly to settle matters.
"Peace will only prevail when the Kremlin will bring in its troops. As it did in Crimea," he said.
Vasilyeva reported from Kiev.
Associated Press writers Yuras Karmanau in Donetsk and Laura Mills and Jim Heintz in Moscow also contributed to this report.