"A military helicopter belonging to Azerbaijan's state border service crashed today at Garakheybat airfield in the Khyzy region at approximately 10:40 (GMT 0640) while conducting a training flight," the ex-Soviet republic's border service and prosecutor general said.

"There are deaths and wounded among the crew," the joint statement said. An investigation is underway into the accident's causes, it added.

The incident came two weeks after Azerbaijan and neighbouring Armenia reported the worst fighting along their shared border since going to war last year over the contested Nagorno-Karabakh region.

The six-week war claimed more than 6,500 lives and ended in November 2020 with a Russian-brokered ceasefire. The deal saw Yerevan cede swathes of territories that it had controlled for decades.

Six Armenian troops and seven Azerbaijani soldiers were killed on November 16 in a flare-up in fighting. A truce was negotiated the same day by Russia's Defence Minister Sergei Shoigu.

Tensions between Baku and Yerevan have been running high since May, when Armenia said Azerbaijan's military crossed its southern frontier to "lay siege" to a lake shared by the two countries.