A drone from the ongoing conflict in Upper Karabakh region crashed in northwestern Iran on Tuesday, according to the official IRNA news agency.

No casualties were reported from the crash, said Ali Amiri, the governor of Khoda Afarin town in East Azerbaijan province.

He said Iranian experts are examining the drone to identify its owners and from where it had taken off.

On Monday, Iran warned Armenia and Azerbaijan over stray fire from their ongoing conflict in the Upper Karabakh region, saying the security of its citizens was a “red line”. This came after missiles struck two villages in the Khudaferin district in East Azerbaijan province, injuring a civilian.

Relations between the two former Soviet republics have been tense since 1991 when the Armenian military occupied Upper Karabakh, or Nagorno-Karabakh, an internationally recognized territory of Azerbaijan.

Some 20% of Azerbaijan's territory has remained under illegal Armenian occupation for nearly three decades.

The OSCE Minsk Group – co-chaired by France, Russia, and the US – was formed in 1992 to find a peaceful solution to the conflict, but to no avail. A cease-fire, however, was agreed to in 1994.

Multiple UN resolutions, as well as international organizations, demand the withdrawal of the occupying forces.

World powers, including Russia, France, and the US, have urged a new cease-fire. Turkey, meanwhile, has supported Baku's right to self-defense and demanded the withdrawal of Armenia's occupying forces.