Azerbaijan, Armenia swap prisoners from Nagorno-Karabakh conflict
Returns had already begun on Monday, Baku's State Commission on Prisoners of War, Hostages and Missing Persons said in a statement, under an "agreement... on the exchange of prisoners and hostages on an 'all for all' basis".
The commission added that "international organisations and the command of the Russian peacekeeping forces" had helped hammer out the deal with Armenia.
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Later Monday, Armenian Prime Minister Nikol Pashinyan announced the return of some of his own country's captured troops.
"Forty-four of our prisoners of war will soon return to Armenia by Russian aircraft," Pashinyan wrote on Facebook.
Baku announced separately on Monday the arrest of four Azerbaijani soldiers, two accused of "defiling" the bodies of Armenian troops who died in battle and the others of destroying tombstones belonging to Armenians.
The men had filmed their actions and shared the videos on social media.
The Azerbaijani Prosecutor General said in a statement that criminal probes had been launched into the incidents, calling them "unacceptable and contrary to the mentality of the Azerbaijani people".
The six-week conflict that erupted in September between Armenia-backed separatists and Azerbaijan over Karabakh ended 10 November with a Moscow-brokered peace deal.
The Armenians ceded swathes of territory and Russian peacekeeping troops were deployed to the region.
More than 5,000 people - including civilians - were killed during the fighting between the ex-Soviet rivals, who fought a war in the 1990s over the mountainous region.