Armenia's defense ministry said Friday (October 2) that Nagorno-Karabakh air defense systems shot down an Azeri warplane and two drones - a report Azerbaijan authorities deny.
Fighting between the two forces has raged for nearly a week around the enclave.
So far, at least 11 civilians have been reported dead and more than 60 wounded in Nagorno-Karabakh, which is part of Azerbaijan, but run by its mostly ethnic Armenian inhabitants.
Nagorno-Karabakh's defense ministry placed the death toll among its forces to at least 158.
A bus carrying Russian and Armenian journalists, as well as a U.S. citizen described as a 'volunteer', was hit by artillery fire, according to the RIA news agency.
Just a day after two French journalists underwent surgery in Nagorno-Karabakh, after being wounded by Azeri shelling.
Also on Friday, Armenia said it would work with Russia, the United States and France on renewing a ceasefire in Nagorno-Karabakh.
Azerbaijan's president ruled out talks with Armenia over the region earlier in the week, and his ally Turkey said Thursday the three big powers should have no role in peacemaking.
The fighting is more serious than at any time since a war in the 1990s in which 30,000 people were killed.
It has deepened concern about stability in the South Caucasus, a region where pipelines carry Azeri oil and gas to world markets.