More than 120 members of European Parliament have urged the EU to increase pressure on Azerbaijan to release Armenian prisoners of war captured last year in fighting over Nagorno-Karabakh, Euroactiv reports.

“We ask you to act to demand the return of all Armenian prisoners of war to their country,” they said, in a letter to the heads of the European Commission, European Council and EU diplomatic service.

It called on the officials — Ursula von der Leyen, Charles Michel and Josep Borrell “to bring all our weight, and use all levers at our disposal, to demand that Azerbaijan purely and solely respect international law”.

Armenia suffered a harrowing defeat in the six-week war last year that left at least 6,000 dead on both sides as Azerbaijan won back swathes of territory it lost in fighting some three decades earlier.

Under a Russia-brokered peace deal on 9 November to halt the bloodshed, the two sides agreed to return all prisoners of war and the remains of those killed in the fighting.

Armenia says it has returned all the captives it took but accuses Azerbaijan of keeping an unknown number of detainees as a bargaining chip.

“It is difficult to precisely draw up the number of remaining prisoners and captives, due to the high number of missing persons and the lack of cooperation from the Azerbaijani side,” the MEPs wrote.

“But it would include 72 people whose captivity Azerbaijan admits, 112 people about whom Azerbaijan did not provide any information, and 61 people whose captivity Azerbaijan categorically denies, but about whom there is concrete evidence to the contrary.”

Azerbaijan insists it has returned all prisoners of war — but does admit it is holding some who were captured in clashes after the peace deal was signed.

Baku has insisted they were not covered by the Russian-brokered agreement and are “terrorist-saboteurs” who should go on trial.

The EU said in a statement last week that all prisoners of war and detained people should be returned “regardless of the circumstances of their arrest”.