RUSSIA'S President Vladimir Putin says that Russia is ready to use all means to protect Russians in Ukraine, but hopes he will not have to use force in eastern Ukraine.
Mr Putin said that while the Ukrainian parliament is legitimate, the acting president is not.
He said fugitive President Viktor Yanukovych is the only legitimate leader of Ukraine.
Mr Putin rejected Western criticism of Russian action in Ukraine, saying that there have been doubts about the legitimacy of Western action in Iraq, Afghanistan and Libya.
It was the first time Mr Putin has spoken publicly since Mr Yanukovych fled Kiev.
He ordered tens of thousands of Russian troops participating in military exercises near Ukraine's border to return to their bases as US Secretary of State John Kerry was on his way to Kiev. Tensions remained high in the strategic Ukrainian peninsula of Crimea with troops loyal to Moscow firing warning shots to ward off protesting Ukrainian soldiers.
The massive military exercise in western Russia involving 150,000 troops, hundreds of tanks and dozens of aircraft was supposed to wrap up anyway, so it was not clear if Mr Putin's move was an attempt to heed the West's call to de-escalate the crisis that has put Ukraine's future on the line.
It came as Mr Kerry was on his way to Kiev to meet with the new Ukrainian leadership that deposed a pro-Russian president, and has accused Moscow of a military invasion in Crimea. The Kremlin, which does not recognise the new Ukrainian leadership, insists it made the move in order to protect Russians living there.
Russian troops who had taken control of the Belbek air base in the Crimea region fired warning shots into the air as around 300 Ukrainian soldiers, who previously manned the airfield, demanded to return.
About a dozen Russian soldiers at the base warned the Ukrainians, who were marching unarmed, not to approach.
They fired warning shots into the air and said they would shoot the Ukrainians if they continued to march toward them.
The shots reflected tensions running high in the Black Sea peninsula since Russian troops, estimated by Ukrainian authorities to be 16,000 strong, tightened their grip on the Crimean peninsula over the weekend.
Ukraine has accused Russia of violating a bilateral agreement on conditions of a Russian lease of a naval base in Crimea that restricts troop movements.
But Russia has argued that it was acting within the deal's limits. Earlier today, the Kremlin said Mr Putin ordered troops participating in military exercises alongside Russia's western border to return to their permanent bases and this was in line with a plan to complete the exercise early this week.
In Brussels, meanwhile, the ambassadors of NATO's 28 member nations will hold a second emergency meeting on Ukraine today after Poland, which borders both Russia and Ukraine, invoked an article calling for consultations when a nation sees its "territorial integrity, political independence or security threatened," the alliance said in a statement.
President Barack Obama has said that Russia is "on the wrong side of history" in Ukraine and its actions violate international law.
Mr Obama said the US was considering economic and diplomatic options that will isolate Russia, and called on Congress to work on an aid package for Ukraine.
In return, Russia's agricultural oversight agency issued a statement declaring the reversal of its earlier decision to lift the ban on imports of US pork. The statement said the existing US system of checks don't guarantee its safety.