Missiles fired by opposing sides in the Nagorno-Karabakh war hit a district in Iran's East Azerbaijan province, south of the Azerbaijan-Armenia border, Iranian state media said Thursday.
Ten missiles landed in two villages in the Khudaferin district, injuring a civilian when rockets hit a house, IRNA News Agency quoted the district's Governor Ali Emiri Rad.
Iran warned Armenia and Azerbaijan following the incident.
"The security of our citizens living in border regions is the red line of our armed forces," Foreign Ministry spokesman Saeed Khatibzadeh said in a statement.
He said next time, Iran would not remain indifferent.
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.
Recent clashes erupted Sept. 27, and since then, Armenia has continued attacks on civilians and Azerbaijani forces.
Turkey has supported Baku's right to self-defense and demanded the withdrawal of Armenia's occupying forces.
Azerbaijan's Prosecutor General's Office said Thursday that at least 43 civilians have been killed and 218 injured in the new Armenian attacks.
Attacks have also rendered 1,592 houses, 79 apartments and 290 public buildings unusable.
