Ukraine army on full alert as Russia backs sending troops
Acting President Olexander Turchynov said he had also stepped up security at key sites, including nuclear plants.
Russia’s Vladimir Putin requested extra troops to protect Russian interests in Ukraine. It came on a day of pro-Russia rallies in the country.
The move has been met with alarm from Western leaders.
President Putin had a 90-minute phone call with US President Barack Obama in which, the Kremlin said, he made clear that Moscow reserves the right to protect its interests and those of Russian speakers in Ukraine.