DONETSK, Ukraine, April 12 (Xinhua) -- The regional police chief here has agreed to demands to resign by pro-Russian protesters who occupied his headquarters Saturday, hours after a dozen gunmen seized two buildings in another eastern Ukraine town.
"As you demanded, I am stepping down," police chief Kostyantyn Pozhydayev told the protesters, who entered the headquarters in the regional capital wearing uniforms of Ukraine's former riot police.
Earlier in the day, about a dozen gunmen seized a state security building and a police station in Slavyansk, a town about 100 km north of Donetsk.
The armed men initially occupied the police station, where they seized at least 400 handguns and 20 automatic weapons, Ukraine police said in a statement.
"The aim of occupying (the police station) was the guns ... they are giving these guns to participants in the protest in Slavyansk," the statement said.
The attack on the police station was followed up with the storming of the state security building.
Ukraine Interior Minister Arsen Avakov said on his Facebook account the attack was led by "armed men in camouflage fatigues" and he vowed a severe response.
Ukrainian special forces had been dispatched to the scene, Avakov said, adding there was zero tolerance for armed terrorists.
Casualties and hostages remain unknown.
After the two incidents, Ukraine's acting foreign minister Andrii Deshchytsia urged Russia to stop "provocative actions" by its agents in eastern Ukraine during a phone call with Russian counterpart Sergei Lavrov, who denied providing any support to the local militants.
Meanwhile, Donetsk separatist leader Sergiy Tsyplakov claimed responsibility for the raid on the police station in a statement issued to Russia's state-run RIA Novosti news agency, but insisted his people were not armed.
A new wave of unrest erupted in Ukraine's east last weekend, when pro-Moscow activists seized several government buildings in the cities of Donetsk, Lugansk and Kharkov, demanding a referendum on autonomy and closer ties with Russia.
On March 18, Russian President Vladimir Putin and Crimean leaders signed a treaty to make the southern peninsula part of Russian territory after almost 97 percent of Crimean voters backed secession from Ukraine in a referendum.
Kiev has rejected the referendum and Crimea's integration into Russia, saying it was unconstitutional.