Russia sent fighter jets to patrol the border with Ukraine, reportedly gave shelter to the country's fugitive president and stood by as pro-Russian gunmen stormed offices of a strategic region, deepening the crisis for Ukraine's new government even as it was being formed.
The moves pose an immediate challenge to Ukraine's new authorities as they seek to set up an interim government for the country, whose population is divided in loyalties between Russia and the West.
Ukraine's new prime minister said the country's future lies in the European Union but with friendly relations with Russia. Some 150,000 Russian soldiers carried out military exercises and fighter jets patrolled the border.
A respected Russian news organisation reported that President Viktor Yanukovych, who was driven out of Kiev by a three-month protest movement, was staying in a Kremlin sanatorium just outside Moscow.
"I have to ask Russia to ensure my personal safety from extremists," Yanukovych said in a statement carried by Russian news agencies today.
He said he still considers himself president.
Shortly after, the same three Russian news agencies quoted an unnamed Russian official saying that Yanukovych's request for protection "was satisfied on the territory of Russia."
Oleksandr Turchynov, who stepped in as acting president after Yanukovych's flight, condemned the takeover of government buildings in Crimea as a "crime against the government of Ukraine."
He warned that any move by Russian troops off of their base in Crimea "will be considered a military aggression."
"Unidentified people with automatic weapons, explosives and grenades have taken over the governmental buildings and the Parliament building in the autonomous region of Crimea," he said.
"I have given orders to the military to use all methods necessary to protect the citizens, punish the criminals, and to free the buildings."
In Kiev, lawmakers chose Arseniy Yatsenyuk as the new prime minister. He will face the hugely complicated task of restoring stability in a country that is not only deeply divided politically but on the verge of financial collapse.
The 39-year-old served as economy minister, foreign minister and parliamentary speaker before Yanukovych took office in 2010, and is widely viewed as a technocratic reformer who enjoys the support of the US.