LUHANSK, Ukraine (AP) -- Ukrainian authorities on Wednesday warned that they are prepared to use force to clear several government buildings seized by pro-Russian separatists in the east of the country.
Protesters continued to occupy the headquarters of Ukraine's Security Service in the eastern city of Luhansk, with hundreds of supporters camped outside and shouting "Putin! Putin!" in support of the Russian President.
The security agency had earlier said that the separatists inside the building, armed with explosives and other weapons, allowed 56 hostages to leave the building during the night. A spokeswoman said there were no other hostages.
But Tetyana Pohukay, a regional police spokeswoman, disputed that statement, saying there had never been any hostages inside, according to the Interfax news agency.
The Luhansk security services building was among several government offices seized by pro-Moscow groups Sunday in an escalation of protests against the interim government in power since the ouster of President Viktor Yanukovych in February.
Serhiy Tyhipko, a lawmaker associated with the previous Ukraine government, urged the authorities not to storm the building in Luhansk but rather negotiate a peaceful solution. Tyhipko said the protesters were demanding to turn Ukraine into a federal state with broad regional autonomy, not to secede.
"The people are not bringing up the issue of breaking off from Ukraine and are not calling for the help of foreign countries," Tyhipko said on his Facebook page.
Turning Ukraine into a federation is Russia's key demand and the new government in Kiev has refused to fulfill it, calling it a precursor to a break-up. In Donetsk, where protesters were still occupying the government building, the regional governor was meeting with key figures in the pro-Russian protest movement to try to find a solution to the crisis
In Donetsk, where protesters were still occupying the government building, the regional governor Serhiy Taruta was meeting with key activists at a hotel to try to find a solution to the crisis.
All the cities affected by the uprisings are in Ukraine's industrial Russian-speaking heartland in the east, which has a large population of ethnic Russians and economic and where cultural ties to Russia are strong. Many residents are suspicious of government that took power in February.
Interior Minister Arsen Avakov said the standoff in Luhansk and the two neighboring Russian-leaning regions of Donetsk and Kharkiv must be resolved within the next two days.
"I want to repeat that there are two options: political settlement through negotiations and the use of force," Avakov told reporters. "We are ready for both options."
Avakov was speaking as anti-government protesters in Luhansk erected high barricades along a thoroughfare running in front of the security service premises.
Overnight, speakers at a gathering in front of the building condemned the government in Kiev and renewed demands to be allowed to hold a referendum on declaring autonomy for their region. That demand is similar to one that preceded Crimea's annexation by Russia.
The Ukrainian government and the U.S. have accused Moscow of fomenting the unrest as a pretext for another Russian military incursion similar to last month's takeover of Crimea. Up to 40,000 Russian troops are massed along the Ukrainian border, according to NATO.
Speeches at the rally were occasionally interspersed with chants of "Russia! Russia!" and an unidentified speaker won cheers as he listed names of prominent politicians that he suggested should be executed.
Those occupying the building have issued a video statement warning that any attempt to storm the place would be met with force.
In the video, posted by Ukrainian media, a masked man identified the occupiers as Ukrainian veterans of the Soviet war in Afghanistan and warned the authorities against trying to retake the building. "Welcome to hell, then!" he said.
The security services said negotiations with the separatists were continuing and that parliamentary deputies had been able to enter and leave the building unhindered.
The Russian Foreign Ministry hit back at the West on Wednesday, calling for the U.S. to stop using international organizations as a means of "exacerbating tensions surrounding Ukraine."
"The daily activity of Russian troops on national territory does not threaten the security of the U.S. or other member states of the OSCE," the Russian statement said. "Attempts to accuse Russia of a buildup of troops are unfounded."
Poland's Prime Minister Donald Tusk on Wednesday called on Moscow to ease tensions.
Speaking after talks with visiting prime minister of Latvia, Laimdota Straujuma, Tusk said that it is "beyond any doubt, that the country that has contributed to this conflict -- Russia -- is responsible for the de-escalation."
Maria Danilova in Kiev, Laura Mills in Moscow and Monika Scislowska in Warsaw, Poland, contributed to this report.