Russia is taking measures to ensure the security of its Black Sea naval fleet based on Ukraine's Crimean peninsula, Russia's defence minister said Wednesday as President Vladimir Putin ordered snap checks of the armed forces.

"We are watching carefully what is happening in the Crimea, what is happening around the Black Sea fleet. We are taking measures to ensure security of sites, infrastructure and arsenals of the Black Sea fleet," minister Sergei Shoigu said, Russian news agencies reported.

The comments came as brawls erupted near the regional parliament building in Crimea's main city of Simferopol between pro-Russian demonstrators and members of Crimea's ethnic Tatar Muslim community, which back the new leadership in Kiev.

The Russian Black Sea fleet is based in the city of Sevastopol on the Crimean peninsula, a mostly Russian-speaking region that was only incorporated into Ukraine in the 1950s when it was part of the Soviet Union.

Sevastopol, which has hosted the Black Sea fleet since tsarist times, has witnessed several pro-Russian demonstrations in recent days with hundreds rallying outside city hall on Tuesday.

President Vladimir Putin has not yet publicly commented on the regime change in Kiev at the weekend, where protesters have deposed President Viktor Yanukovych who fled the capital and has not been seen since Saturday.

After returning from the Winter Olympic host city Sochi, Putin called the security council together on Tuesday to discuss the situation in Ukraine, the Kremlin website said. None of Putin's remarks was carried by the media.

On Wednesday Putin ordered a snap check of the battle-readiness of the armed forces in the west and centre of the country, including the area bordering Ukraine.

"Generally speaking, the drill is not in any way related to the events in Ukraine," Shoigu said.

But he said it will include military exercises "on Russia's borders with other countries, including Ukraine".

"The commander-in-chief has set the task of checking the capability of the armed forces to deal with crisis situations posing a threat to the military security of the country," Shoigu told journalists.

The drill involves army, navy and airforce troops based in the western military district, a vast territory bordering Ukraine, Belarus, the Baltic states, Finland and the Arctic.

The drill will include 150,000 servicemen, 90 airplanes, 880 tanks, and up to 80 ships, he said. It started on Wednesday at 2:00pm (1000 GMT) and will last until March 3.

Putin ordered a similar check last year and said at the time that such drills should become regular events.

The last such check was carried out in July last year, involving more than 80,000 troops in far eastern Russia. It was the largest such snap check since the breakup of the Soviet Union in 1991.