Putin submitted his request to Russia's upper house of parliament, the Federation Council, on Saturday asking for the approval of the use of armed forces in Ukraine, the Kremlin said.

"I'm submitting a request for using the armed forces of the Russian Federation on the territory of Ukraine pending the normalization of the socio-political situation in that country," he said in a statement released by the Kremlin.

Using Russian armed forces abroad only requires approval from the Federation Council. No preliminary OK is necessary from the lower house of parliament, the Duma.

Crimea's pro-Russian Prime Minister Sergei Aksyonov had earlier asked Moscow for help in restoring calm the region, after claiming control of the military and police there. The appeal was followed by the Duma calling on Putin to "stabilize" the crisis in Crimea using all means possible.

On Friday armed men described as Russian soldiers took control of key airports and a communications center in Crimea. Ukraine's new pro-Western government has accused Russia of a "military invasion and occupation" in the region, which is where Moscow's Black Sea Fleet is based.

Calls for calm

Ukrainian Prime Minister Sergei Arseny Yatsenyuk said at the opening of a Cabinet meeting in Kyiv that Russia should stop trying to provoke unrest in Crimea.

"We call on the government and authorities of Russia to recall their forces, and to return to their stations," Yatsenyuk was quoted as saying by the Interfax news agency. "Russian partners, stop provoking civil and military resistance in Ukraine."

European leaders have urged Ukraine and Russia to avoid taking action that could spark a military conflict. German Foreign Minister Frank-Walter Steinmeier said in a statement that the Kremlin should respect Ukraine's sovereignty.

"Whoever continues to pour oil into the fire now - in words or in deeds - is knowingly heading towards an escalation of events," he said.

Ukraine has been deeply divided along pro-Western and Russian lines since protests broke out in November following then-President Viktor Yanukovych's decision to reject an EU trade deal in favor of strengthening ties with Russia. Increased protests last week culminated in Yanukovych stepping down from office and fleeing to the country.

Rallies in Ukraine

Pro-Russia demonstrations have since been held around Ukraine. On Saturday, several thousand protesters clashed with supporters guarding Kharkhiv's city hall and raised the Russian flag over the building. Dozens of people were reportedly injured in the violence.

Ukrainian TV and news agencies also reported rallies in Donetsk and Odessa, which along with Kharkhiv have large Russian-speaking populations.

dr/pfd (AP, dpa, Reuters, AFP)