Upon occupying the building, protesters discarded the Ukrainian flag and replaced it with that of the "Donetsk People's Republic" — a movement that seeks either greater autonomy from the central government or independence and possible annexation by Russia.

In the regional capital city, Donetsk, anti-government demonstrators took over the regional prosecutor's office Thursday. Several dozen riot police standing guard fired stun grenades and tear gas when people at the front of the crowd of several hundred attempted to force their way inside.

The order didn't specify where conscript-bolstered forces would be deployed. Earlier in the week, Turchynov said police and security forces had been effectively "helpless" against an insurgency in the Donetsk and Luhansk regions and that efforts should be focused on preventing its spread to other parts of the country.

Although Ukraine announced last year that it would end military conscription and become an all-volunteer force, Turchynov said in his order that the draft must be renewed in light of "threats of encroachment on Ukraine's territorial integrity and interference by Russia in the internal affairs of Ukraine."

The move came hours after Russian President Vladimir Putin said that Ukraine should withdraw its military units from the eastern and southern regions of the country, where pro-Russian groups have been seizing buildings.

Ukraine has reinstated military conscription to deal with a spreading pro-Moscow insurgency in its east, according to a decree issued Thursday by acting President Oleksandr Turchynov.

Continued unrest

Donetsk is the heartland of support for Russia-friendly former President Viktor Yanukovych, who was ousted in February after months of protests in the capital. Opponents of the government that succeeded him have seized buildings in about a dozen cities and towns in eastern Ukraine.

Local news website Novosti Donbassa reported that earlier in the day about 30 armed men arrived in six cars in the town of Amvrosiivka, which lies close to the Russian border, took over the City Council and forced the mayor to resign.

On Wednesday, activists took control of the customs service building in Donetsk and the City Hall in Alchevsk, an industrial center of about 110,000 people, adding to the scores of buildings taken by the separatists over the past month in the east, where a dozen cities are now in their hands.

There has also been a spate of reported kidnappings of pro-government politicians. The Svoboda nationalist party said a local party branch leader in Kostiantynivka, 40 miles north of Donetsk, initially managed to fight off attackers at his home, but was taken away as he was phoning for help.

The armed element of the insurgency is focused on Slovyansk, a city 70 miles north of Donetsk in which seven European observers from the Organization for Security and Cooperation in Europe remain held by pro-Russian gunmen.

German Chancellor Angela Merkel on Thursday again called Putin and asked for his assistance in freeing the group. A spokeswoman for Merkel said the focus of the phone conversation between the two leaders was on "the continuing hostage-taking of the OSCE observers by separatists in eastern Ukraine." Spokeswoman Christiane Wirtz said in a statement that Merkel "appealed to the president to use his influence" in resolving the situation.

Russia denies allegations from Kyiv and the West that it is influencing or fomenting the unrest in eastern Ukraine. The Kremlin confirmed the conversation and said Putin stressed that "the main thing was for Ukraine to withdraw its troops from southeastern Ukraine, stop the violence and quickly start a broad national dialogue on constitutional reform."

Wire services