2014

April 6: Pro-Moscow demonstrators seize government buildings in towns and cities in Ukraine’s east.

April 13: Kiev announces the launch of an “anti-terrorist” operation in the east.

May 11: Voters call for independence in referendums in Lugansk and Donetsk, rejected as illegitimate by Kiev and the West.

May 25: Poroshenko wins Ukraine’s presidential polls.

June 27: The EU and Ukraine sign the association agreement whose rejection had sparked the initial unrest.

July 17: Malaysia Airlines flight MH17 is shot down over rebel-held territory, killing 298 people.

July 29: The EU, US broaden sanctions on Russia.

Aug. 25: Rebels mount a counter-offensive in the southeast, reportedly backed by Russian troops and heavy weapons.

Sept. 5: Cease-fire signed in Minsk but violence continues.

Oct. 26: Pro-Western parties win the most seats in a general election that was boycotted in the east.

Nov. 2: Separatists in eastern Ukraine vote in Russian-backed leadership elections.

Nov. 12: NATO accuses Russia of sending fresh columns of tanks, troops into Ukraine.

Dec. 9: A new cease-fire is declared as part of a surprise agreement between Kiev and the rebels.

Dec. 23: Ukraine drops its non-aligned status, allowing it to possibly join NATO.

Dec. 24: A new round of talks gets underway in Minsk between Kiev, Moscow, the pro-Russian separatists and OSCE envoys.

2015

Jan. 13: A rocket slams into a bus carrying civilians, killing 13, in Volnovakha, Ukraine.

Jan. 18: Ukrainian tanks repel a strong rebel offensive against the airport in Donetsk.

Jan. 19: Kiev says that the rebels have been reinforced with Russian weapons and almost 700 soldiers. Moscow denies the claim.

Jan. 20: Ukrainian President Petro Poroshenko cuts short a visit to Davos due to deadly clashes in the east.

Jan. 21: Poroshenko says that there are more than 9,000 Russian soldiers in eastern Ukraine to back up the separatists. In Berlin, European leaders call for an end to the fighting and a withdrawal of heavy weapons.

Jan. 22: Shelling hits a trolleybus in Donetsk, killing at least 13 people.

Ukraine says its soldiers have been forced to pull out of most of Donetsk airport and that at least 10 troops were among the 34 people killed in the previous 24 hours.