Pro-Russia rebels ignore Kyiv’s ultimatum to leave occupied buildings

President Barack Obama told Russian President Vladimir Putin in a tense phone call Monday that while a diplomatic solution to the crisis in Ukraine remains open, Russia's actions have not been "conducive" to that approach and that sanctions against Russia would increase if its military actions in eastern Ukraine persist. 

Earlier Monday, pro-Russian armed rebels ignored an ultimatum from Ukraine's interim President Oleksandr Turchynov to leave government buildings being occupied in the country's east or face a military action — an offensive that has so far failed to materialize.

In a call that the White House said Moscow requested, Obama told Putin that those forces were threatening to undermine and destabilize the government in Kyiv and requested that Putin withdraw his troops from the border and buildings they seized.

Putin said reports of Russian interference in the region are wrong and stressed that Kyiv should focus on engaging all parts of the country in drawing up a new constitution. Obama said Ukraine's central government has made real offers to address concerns about giving local governments more power but reiterated his belief that Ukrainians must decide those matters — most notably in the presidential election on May 25. 

As the 9 a.m. local time deadline passed, there were seemingly few signs that the rebels were prepared to leave their barricades. Moreover, in an apparent further challenge to Turchynov to make good on his threat, a group of rebels stormed and seized a police headquarters in Horlivka, close to Ukraine's border with Russia.

Turchynov insisted on Monday that an offensive against the rebels would take place. But he sacked the state security chief in charge of the operation shortly after making the comment — signaling possible discord behind the scenes. Obama praised the Ukrainian government for displaying "remarkable restraint" despite the combative rhetoric from Russian officials.

Turchynov urged the United Nations to send peacekeeping troops to eastern Ukraine. In a telephone call with Secretary-General Ban Ki-moon, Turchynov suggested that an "anti-terrorist operation" be conducted jointly by Ukrainian security forces and U.N. peacekeepers, according to the presidential website.

Peacekeepers, however, would have to be authorized by the U.N. Security Council, where Russia holds veto power.

Meanwhile, Russian Foreign Minister Sergey Lavrov on Monday said Kyiv was "demonstrating its inability to take responsibility for the fate of the country" and warned that any use of force against Russian speakers "would undermine the potential for cooperation," including talks due to be held on Thursday among Russia, Ukraine, the United States and the European Union. 

Lavrov also said that it was not in Russia's interest for the former Soviet republic to split but that Moscow wanted all citizens of Ukraine to be given equal treatment under the law. Russia has amassed troops on the border with Ukraine for the stated purpose of protecting ethnic Russians who live in its eastern region. However, Kyiv and its allies allege the troops are there for purposes of intimidation.

"What the Russians are clearly trying to do is to use something called coercive diplomacy," Robert Donaldson, director of the Russian studies program at the University of Tulsa, told Al Jazeera. "They've got their forces across the border. They're trying to bring about some concessions on the part of the authorities in Kyiv and so the threat of force looming there. [It] certainly has got everybody’s attention, and that gives the Russians, they think, better bargaining power." 

Turchynov, for his part, was angered by the death of a state security officer and the wounding of two other officers near the eastern city of Slovyansk, where armed men seized two government buildings, and he warned the pro-Russian groups on Sunday that a full-scale security operation would be unleashed unless they met the deadline.

"We will not allow Russia to repeat the Crimean scenario in the eastern regions of Ukraine," Turchynov said on Sunday night. Crimea was annexed by Russia in March after a referendum that the international community regards as illegitimate. 

Turchynov and other leaders blame Russia for inspiring and organizing a rash of rebellions in Slovyansk and other Russian-speaking towns in eastern Ukraine after months of turmoil that saw Moscow-backed former President Viktor Yanukovych flee the country.

Use of force by Kyiv's pro-Europe authorities could trigger a fresh confrontation with Russia. The crisis has brought relations between Russia and the West to their lowest point since the end of the Cold War in 1991.

Russia's Foreign Ministry called the planned military operation a "criminal order" and said the West should bring its allies in Ukraine's government under control. 

The United Nations Security Council held an emergency session on Sunday night, and the United States warned that it was likely to impose further sanctions against the Kremlin if the escalation in eastern Ukraine continues.

The EU and the United States have already imposed limited sanctions on Moscow since its annexation of Crimea. Obama said Monday the costs of these measures would increase if military action persists.

With East-West relations in crisis, NATO described the appearance in eastern Ukraine of men with specialized Russian weapons and matching uniforms without insignia — like those worn by Moscow's troops when they seized Crimea — as a "grave development."

SLIDESHOW: TENSIONS ESCALATE IN EASTERN UKRAINE