Saturday, February 22: Ukraine's parliament votes to remove President Viktor Yanukovych and frees jailed opposition leader Yulia Tymoshenko.
Sunday, February 23: Parliament gives interim presidential authority to the speaker, Oleksandr Turchynov, a leader of the opposition. In Crimea, pro-Russian protesters rally against the new government.
Monday, February 24: An arrest warrant is issued for Yanukovych for his role in the deaths of dozens of protesters killed by riot police.
Tuesday, February 25: A Russian flag is raised on a major government building. Crowds scuffle in Kharkiv, a large city in eastern Ukraine.
Wednesday, February 26: Moscow orders what it says are routine military exercises in a district bordering Ukraine and puts troops in the region on high alert. U.S. Secretary of State John Kerry says any Russian military intervention would be a "grave mistake."
Thursday, February 27: Pro-Russia gunmen take over the regional parliament building in Crimea. Yanukovych, who hadn't been heard from in days, resurfaces in Russia.
Friday, February 28: Heightened Russian military activity in Crimea prompts a warning from President Barack Obama, who says there "will be costs for any military intervention." The new Ukrainian government says hundreds of soldiers in green camouflage, but without insignia, have taken over two airports in Crimea.
Saturday, March 1: Russia's lower house of parliament grants Putin permission to send troops to Ukraine. Crimea's pro-Russian leader claims control of the military and police in the region.