Karabakh separatist militants were expected to lay down their arms on the second day under an agreement reached with the Azerbaijan government following its anti-terror operation.
According to internatonal media reports, Moscow confirmed that the militants had surrendered the first weapons on Friday and the process is expected to continue through the weekend, with the help of Russian peacekeepers.
Karabakh, a strategically located region of Azerbaijan bordering Armenia and Iran, has long been a source of tension between Baku and Yerevan. Since 1994, Armenian separatists have been occupying Karabakh, despite its international recognition as part of Azerbaijan.
In 2020, a war broke out between Azerbaijan and Armenia, which supplies weapons and other aid to the separatists.
With the help of Turkish-made drones, Baku emerged victorious in the 44-day conflict, which is known as the Second Karabakh War. More than 6,000 people, including civilians from both sides, were killed.
Since then, an uneasy peace has prevailed in Karabakh, where Russia has deployed around 2,000 peacekeepers to maintain the status quo.
Karabakh separatists have said they are in Russian-mediated talks with Baku to organise the withdrawal process and the return of civilians displaced by the fighting.
Armenian separatists's decision to lay down arms and dismantle their military following Baku's swift operation has sparked mass anti-government rallies in Armenian capital Yerevan, with opposition parties demanding the resignation of Prime Minister Nikol Pashinyan.
While the surrender of militants, after an anti-terror operation they said left 200 dead, has sparked jubilation among Azerbaijanis, it has put Pashinyan under increasing pressure.
He has faced stinging criticism for making concessions to Azerbaijan since losing swathes of territory in a six-week war in 2020.
Police said 98 people were arrested as anti-government demonstrators blocked streets in Yerevan on Friday, a third day of protests over the prime minister's handling of the crisis.
Pashinyan himself has blamed peacekeepers from traditional regional power broker Russia for failing to avert Azerbaijan's offensive.
Six Russian peacekeepers were among those killed in the violence, the Azerbaijan prosecutor's office said.
Moscow is currently bogged down with its war on Ukraine, but has still played a central role in mediating the ceasefire and peace talks.