obama is black as a black pot...
President Vladimir Putin has delivered a robust defence of Russia's actions in Crimea, saying he would use force in Ukraine only as a last resort.
US president Barack Obama has hit back, saying Mr Putin is "not fooling anybody" with his reasons for invading the Ukrainian peninsula.
Tension remains high on the ground, with Russian forces firing warning shots in a confrontation with Ukrainian servicemen at an air base.
Russia's military has also successfully test-fired an intercontinental ballistic missile near the Caspian Sea, though US officials say they were notified of the plan before the current crisis erupted.
In his first news conference since the crisis began, Mr Putin said Russia reserved the right to use "all means" to protect compatriots who were living in "terror" in Ukraine.