Ukraine truce shaken by new shelling
The truce held for much of Saturday but shelling in Mariupol, which killed one woman, was followed by the Donetsk airport blasts early on Sunday.
The truce and 12-point peace roadmap was signed at talks involving Ukraine, Russia, the rebels and the OSCE.
Fighting in the east has left some 2,600 people dead since April.
Russia has repeatedly denied accusations by Ukraine and the West that it has been sending regular troops into eastern Ukraine to help the rebels, who want to establish an independent state.