Iran said an unidentified drone crashed near its border with Azerbaijan on Tuesday, as Baku and Yerevan accused each other of violating a truce in fighting over Nagorno-Karabakh.
The drone crashed in a village in Parsabad county, Ardebil province, along Iran's northern border, deputy governor Behrouz Nedayi told state news agency IRNA.
"The drone's identity and cause of its crash in the area are being investigated," he said, reporting no damage.
According to IRNA, the drone "may belong to Azerbaijan or Armenia's army given the fighting beyond Iran's northern border".
The two neighbours have for decades been locked in a dispute over Nagorno-Karabakh, an ethnically Armenian area which broke away from Baku in a 1990s war that cost about 30,000 lives.
Heavy fighting erupted on September 27 in one of the most combustible frozen conflicts left over from the collapse of the Soviet Union.
Armenian and Azerbaijani foreign ministers agreed Saturday to a humanitarian ceasefire, but repeated clashes have battered the truce deal.
Iran has called on both sides to cease hostilities and offered to facilitate talks. It has also warned against any "intrusion" after mortar fire hit Iranian villages along the border.
The Islamic republic itself is home to a large Azeri community, mainly in the northwest.
According to some estimates, Azeris make up 10 million of the 80-million population of Iran, which is also home to almost 100,000 Armenians.