Local Armenian officials say an explosion at a fuel depot in Nagorno-Karabakh, Azerbaijan has killed 20 people and injured hundreds.

Nearly 300 people were admitted to hospitals, dozens of whom are "still in critical condition". It came as the Armenian government said 13,350 refugees had entered the country from the enclave.

It is not yet clear what caused the explosion on Monday evening near the main city of Khankendi, known to Armenians as Stepanakert.

Thousands of people tried to leave the area, overwhelming petrol stations, which were already struggling with fuel shortages after a month-long blockade.