A Saudi-based 57-member Muslim body on Sunday demanded Armenia's "unconditional" withdrawal from the Nagorny Karabakh region after clashes with Azerbaijani troops left 30 soldiers dead.
The Organisation of Islamic Cooperation, of which Azerbaijan is a member, condemned "the attack by Armenian forces on the borders of occupied Azerbaijani territories" and Yerevan's "disrespect of the (unilateral) cease-fire" announced by Baku. On Saturday, fierce clashes left at least 18 Armenian and 12 Azerbaijani soldiers dead after both sides accused each other of attacking with heavy weaponry across the volatile frontline.
Ethnic Armenian separatists backed by Yerevan seized control of the mountainous Nagorny Karabakh region in an early 1990s war that claimed some 30,000 lives, and the foes have never signed a peace deal despite a 1994 cease-fire.
The region is still internationally recognised as part of Azerbaijan and the two sides frequently exchange fire, but the latest episode marked a surge in violence and sparked frantic appeals for peace from international powers. OIC Secretary General Iyad Madani demanded "the immediate, unconditional, and complete withdrawal of Armenian forces from the region and other occupied Azerbaijani territories."
He called for increased international efforts, notably by the so-called Minsk Group, to urgently reach a political settlement that would "preserve" Azerbaijan's territories.
The Minsk Group, co-chaired by France, Russia and the United States, leads efforts by the Organisation for Security and Co-operation in Europe (OSCE) to find a solution to the conflict.
Energy-rich Azerbaijan, whose military spending has in the past exceeded Moscow-backed Armenia's entire state budget, has repeatedly threatened to take back the breakaway region by force if negotiations fail to yield results.