"A US-brokered ceasefire between Armenia and Azerbaijan appears to have failed within minutes.
The humanitarian ceasefire was the third attempt to pause almost a month of fighting that has killed about 5,000 people and displaced tens of thousands, in the worst outbreak of hostilities between the two countries for decades.
Both countries' governments said they had adhered to the 8am truce but accused the other of launching artillery barrages on military positions and civilian areas.
The intense fighting, which has been marked by the use of long-range artillery and armed drones, and the failure of two previous Russia-brokered ceasefires, has raised fears that the conflict could drag in other powers such as Turkey and Russia."