A security official was killed and two people were wounded when a shooter opened fire at Azerbaijan's embassy in Iran, Azerbaijan's foreign ministry said on Friday.
"The attacker broke through the guard post, killing the head of security with a Kalashnikov assault rifle," it said.
Video shared on social media showed what appeared to be broken glass and damage to a door inside the embassy building.
Police in Tehran said they have arrested a suspect and are investigating the motive behind the attack.
The suspect entered the embassy with two young children and may have been motivated by "personal issues", Iran's semi-official Tasnim news agency reported, citing the police chief.