Clashes between Azerbaijani and Armenian forces killed at least 13 people on Monday in a third day of fighting over Nagorno-Karabakh, as Turkey fuelled tensions following the worst violence in decades in the disputed territory.
Russia and the West have scrambled to call for an end to the fighting, but Turkish President Recep Tayyip Erdogan, a firm ally of Azerbaijan, insisted that the Armenian-controlled region would "one day" return to Baku's control.
On the ground, the death toll since fighting erupted on Friday night rose to 46 after Armenia's defence ministry said five Armenian "volunteer" fighters were killed when a bus in which they were travelling was hit.
Earlier the Armenia-backed separatist authorities in Karabakh — which claims independence but is supported by Yerevan — said three civilians and two more soldiers were killed in fierce shelling.
Baku said three of its troops were killed overnight when Armenian forces shelled its positions using mortars and grenade launchers.
Azerbaijan has claimed to have captured several strategic positions inside Karabakh, which is internationally recognised as part of Azerbaijan, in what would be the first change in the frontline since an inconclusive ceasefire ended a war over the region in 1994.
Armenian President Serzh Sarkisian said a "ceasefire would only be possible if the militaries of both sides return to the positions" they held prior to the outbreak of hostilities.
His comment came a day after Azerbaijan announced a unilateral truce that failed to stop the fighting.