Ukraine's interim prime minister claimed on Monday that the seizure of government buildings in three eastern cities was part of a plan to eventually bring Russian troops into the region.

"An anti-Ukrainian plan is being put into operation… under which foreign troops will cross the border and seize the territory of the country," Arseniy Yatsenyuk told a government meeting in Kyiv. "We will not allow this."

The interim prime minister described the protest organizers as a "group of radicals who coordinate themselves with intelligence services from foreign countries."

Pro-Russian protesters on Sunday night seized official buildings in the cities of Kharkiv, Luhansk and Donetsk, calling for referendums on the regions joining the Russian Federation.

In Donetsk on Monday, protesters were quoted by Interfax Ukraine as proclaiming the creation of a sovereign "people's republic" independent of Kyiv's rule. Interfax reported that the men pledged a referendum on joining Russia no later than May 11.

Last month, the Ukrainian region of Crimea voted in favor of joining Russia in a contentious referendum labeled a violation of international law by Kyiv and NATO.

Yatsenyuk also said on Monday that Russian troops remained within a 30-kilometer (19-mile) zone near the border with Ukraine - contradicting earlier reports of a Russian withdrawal from the border.

Chancellor Angela Merkel's spokesman, Steffen Seibert, said on Monday in Berlin that the German government was "alarmed" by the most recent tensions in eastern Ukraine. He also urged Russia to keep to pledges made in conversations with the chancellor.

"Today we must make it clear that the issue at hand is still that this withdrawal is demonstrably carried out," Seibert said.

Calm in Kharkiv, Luhansk 'arsenal' compromised

Interim Interior Minister Arsen Avakov on Monday said that the main regional administration building in Kharkiv had been cleared of "separatists." Avakov had similarly apportioned blame for the unrest to ousted President Viktor Yanukovych and Russia's Vladimir Putin on Sunday night.

Police in Luhansk said that highway police had closed off roads into the city after the protesters occupying a state security building seized weapons from within.

"Unkown people who are in the building have broken into the building's arsenal and have seized weapons," the police statement said. Nine people have been injured in the unrest in Luhansk.

Ukraine's defense ministry also said on Monday that a Russian marine had shot a Ukrainian naval officer in Crimea on Sunday night. The ministry said it was investigating the incident in Novofedorivka. The 33-year-old was preparing to leave the region, one of a minority of Crimea-based servicemen to stay with the Ukrainian forces and relocate - rather than to stay in Crimea and leave the military.

Russia has not recognized the new leadership in Kyiv, saying it is influenced by the far right and claiming that ethnic Russians in eastern Ukraine are in danger as a result.

msh/hc (AFP, AP, Reuters)