Ukraine standoffs

Armed pro-Russia militants stand guard outside the regional administration building in the eastern Ukrainian city of Slavyansk on Monday. Local police reportedly failed to support the Ukrainian government's ultimatum to pro-Kremlin militias to lay down their weapons, and the gunmen have gone on to seize more facilities in eastern Ukraine. (Genya Savilov / AFP/Getty Images / April 14, 2014)

MOSCOW -- A threatened sweep by Ukrainian armed forces to oust pro-Russia gunmen occupying government buildings in eastern Ukraine failed to materialize after local police in the besieged venues apparently refused to take part in the proclaimed "anti-terrorist operation."

Ukraine's acting president, Oleksandr Turchynov, had issued an ultimatum on Sunday that gunmen holding key government facilities in Donetsk, Luhansk, Slavyansk, Kramatorsk and other cities in the volatile eastern and southern areas of Ukraine lay down their arms Monday or face ouster at gunpoint by Ukrainian troops and police.

Instead of complying, the separatists attacked and seized an airstrip near Slavyansk and an administrative building in the mining town of Horlivka, in the Donetsk region, UNIAN news agency reported.

Preparations for the threatened move against the gunmen were undermined Sunday by an ambush in Slavyansk. The attack on a convoy of  high-ranking Ukraine Security Service officers on the city outskirts killed a senior officer and wounded five others in his detail, the private TSN television network reported.

In an address to Parliament in Kiev on Monday, Turchynov blamed the obvious lack of progress in the declared anti-terrorist operation on widespread sabotage among local police ranks.

"The main problem is that the police, formed in the times of [former President Viktor] Yanukovich, proved incapable of offering resistance to separatism," Turchynov said. "We will renew the police ranks in the nearest time to form a force which will be able to withstand the onslaught of the Russian aggression and separatism."

Ukraine's Interior Ministry was urgently working to replace unreliable local police ranks in the cities occupied by pro-Russia gunmen, said a statement posted on the ministry's website Monday.

"The Interior Ministry is ready to employ over 12,000 men across the country as members of the new units, to provide weapons and uniforms for them as well as guidance by regular [police] commanders," the statement read.

The ambush in Slavyansk was part of "wide-scale military aggression of the Russian Federation," Ukraine Security Service charged.

Turchynov called U.N. Secretary General Ban Ki-moon on Monday to ask for a deployment of U.N. peacekeeping troops to help restore order in the occupied cities, according to the Ukrainian presidential website. But any mission by the world body would require U.N. Security Council approval, and Russia as a permanent member wields veto power that it would be expected to use  to block outside intervention.

U.S. and European officials also accuse the government of Russian President Vladimir Putin of inciting the armed takeovers of Ukrainian sites as part of a plot to unsettle and divide Ukraine ahead of its May 25 presidential election and restoration of legitimate leadership.

Ukraine's Security Service released what it said was evidence of Russian direction of the unrest: a recording and transcript of a Russian-speaking leader of the militants in Slavyansk consulting with a coordinator across the border in Russia.

In the recording, the commander code-named Shooter was heard informing his coordinator on the results of the ambush in which the senior Ukrainian officer was killed.

"Who did we put down? They must have been some big fish," Shooter is heard to say. His report also included a claim that his gunmen had opened fire on the convoy without losing any of their occupied positions.

"So you got the right guys," the voice said to be the Russian director is heard to say, adding that the Palm Sunday operation to deter a Ukrainian forces' sweep "marked the holiday well."

"I did my best. Thank you," Shooter replied.

Elsewhere in the recording, the alleged Russian coordinator is heard asking Shooter to find someone among the separatist gunmen who can speak with a  Ukrainian accent and articulate demands for a report to be published in the pro-Kremlin online journal Life News. The demands were to include urgent election of regional governors and the "federalization" of Ukraine to grant regions more autonomy in economic and foreign policy.

Ukraine's embattled leadership in Kiev has pledged to discuss constitutional reforms to grant more authority to the regions. Turchynov implied on Monday that Ukraine may hold a referendum, as early as coinciding with the May 25 presidential vote, on whether to remain a unitary state with a strong central government or to become a federation.

"We are not against holding a referendum,” Turchynov said in televised remarks. “What is more, I am sure if Parliament passes a decision to hold such a referendum simultaneously with the presidential election, an overwhelming majority of Ukrainians will vote for an indivisible, independent and unitary Ukraine."

European Union foreign ministers were meeting in Luxembourg on Monday to consider stepped-up sanctions on Russia for its alleged instigation of the disruptions in Ukraine.