Last autumn Armenia's armed conflict with Azerbaijan over the disputed Nagorno-Karabakh region claimed more than 6,500 lives and saw Yerevan cede swathes of territory it had controlled for decades.

The war sparked harsh criticism of Prime Minister Nikol Pashinyan, with opposition parties accusing him of failing to prepare the army for possible large-scale hostilities and betraying national interests by agreeing to a humiliating truce.

Critics say Armenian armed forces were ill-equipped and lacked knowledge of modern warfare, while corrupt officials made a fortune on arms procurement contracts.

On Thursday, Armenia's state security service announced the detention of former defence minister David Tonoyan for alleged "abuse of office, forgery, and embezzlement while procuring weapons for the country's armed forces."

Tonoyan, 53, was appointed defence minister in 2018 and resigned shortly after the six-week war.

He is suspected of misappropriating some $4.7 million, the security service said, adding that "many more former and serving military officials" were being investigated for similar offences.

Ethnic Armenian separatists in Nagorno-Karabakh broke away from Azerbaijan as the Soviet Union collapsed, and the ensuing conflict claimed around 30,000 lives.

At the time, Armenians took control of the enclave as well as seven nearby districts of Azerbaijan -- some 20 percent of the country's national territory.

A fresh war erupted last September and saw the technologically superior Azerbaijani military rout Armenian forces with Turkey's backing.

The war ended in November with a Russian-brokered truce under which Yerevan ceded parts of Karabakh and all of the surrounding districts.

Moscow has deployed some 2,000 peacekeepers in the area to oversee the ceasefire.