Yerevan, Sep 26 : At least 20 people were killed and more than 290 others injured in a fuel depot explosion in the conflict-hit Nagorno-Karabakh region which was seized by Azerbaijan last week, officials said on Tuesday. Seven victims died in hospital, and 13 unidentified bodieswere taken to the coroner's office, Xinhua news quoted Armenia's state-run Armenpress as saying in a report on Tuesday, citing local healthcare authorities. Dozens of the wounded are in critical condition and some are still missing, the report said. A team of medics are en route from Armenia's capital Yerevan to the region by helicopter to help the victims of Monday's explosion in the main city of Stepanakert, it added. The cause of the blast remains unknown. The tragic incident occurred as the Armenian government said that 13,350 refugees hace crossed into the country from the disputed region -- home to a majority of some 120,000 ethnic Armenians -- since the seizure. The Armenian government in Yerevan has announced plans to move those made homeless by the fighting. Envoys from Armenia and Azerbaijan are due to meet in Brussels on Tuesday for European Union-backed talks, reports the BBC. It will be the first time diplomatic talks are held since Azerbaijan seized the enclave last week. The two sides will be represented by their national security advisors. Nagorno-Karabakh -- a mountainous region in the South Caucasus -- is recognised internationally as part of Azerbaijan, but has been controlled by ethnic Armenians for three decades. The enclave has been supported by Armenia and also by their ally, Russia, which has had hundreds of soldiers there for years. Five Russian peacekeepers were killed - alongside at least 200 ethnic Armenians and dozens of Azerbaijani soldiers - as Azerbaijan's army swept in last week. /IANS