Azerbaijan on Sunday accused Armenia of attacking large cities overnight in violation of the cease-fire deal brokered by Russia that seeks to end the worst outbreak of hostilities in the separatist Nagorno-Karabakh region.

The two sides traded blame for breaking the truce that took effect at noon (0800 GMT) with new attacks, and Azerbaijan’s top diplomat said the truce never entered force. The cease-fire announcement came overnight after 10 hours of talks in Moscow sponsored by Russian Foreign Minister Sergey Lavrov. The deal stipulated that the cease-fire should pave the way for talks on settling the conflict. If the truce holds, it would mark a major diplomatic coup