The attacker, identified as Yasin Hosseinzadeh, moved quickly through the embassy compound. He shot and killed Orkhan Asgarov, the head of the embassy's security service and a senior lieutenant, and wounded two other staff members. Embassy personnel fought back. One guard attempted to wrestle the Kalashnikov away, and though he could not disarm the gunman, he managed to shove him out of the building and lock the door. Outside, Hosseinzadeh fired repeatedly at the embassy gate. He then tried twice to set the embassy car ablaze using a gas cylinder he had brought in his trunk, but both attempts failed. During the second try, his own clothing caught fire. Iranian police arrived and detained him shortly after. CCTV footage released that afternoon showed the entire sequence, and the world watched a diplomatic compound turn into a crime scene.

From the moment the gunman was in custody, Iran and Azerbaijan told sharply different stories. Tehran police chief Sardar Hossein Rahimi declared the motive personal: Hosseinzadeh claimed his wife, a Baku native, had visited the embassy in April 2022 and never returned home. He had filed a missing persons report in Urmia, but police closed the case after determining the woman had gone back to Azerbaijan. Frustrated by months of unanswered inquiries, he armed himself. Azerbaijan rejected this explanation entirely. President Ilham Aliyev called the attack a terrorist act and pointed to what he considered suspicious behavior by Iranian authorities, noting that the attacker was quickly interviewed by Iranian media and declared mentally disabled within two days. Rahimi himself was fired within hours, after footage showed an Iranian security guard at the entrance appearing to do nothing as the gunman entered.

The fallout was swift. Azerbaijan evacuated fifty-three embassy staff members from Tehran within two days, leaving only five behind to guard the property. The embassy suspended operations entirely. President Aliyev accepted a condolence call from Iranian President Ebrahim Raisi but made clear his demand for a thorough investigation and full punishment of the perpetrator. The incident echoed a troubling pattern. Azerbaijani diplomatic missions had faced attacks before: in August 2022, the London embassy was stormed by members of the Mahdi Servants Union, who tore down the Azerbaijani flag. Two months later, a car belonging to the Washington embassy was shot at. None of those incidents had been lethal. This one was.

The attack drew broad international condemnation. The United States reminded Iran of its obligations under the Vienna Convention on Diplomatic Relations to protect foreign diplomats. Saudi Arabia stressed solidarity with Azerbaijan. The United Nations emphasized that attacks on diplomatic missions are strictly prohibited under international law. Russia offered assistance. Statements poured in from Turkey, Hungary, France, Croatia, Estonia, and others. The European Commission called for full accountability. At its core, the attack raised a question older than modern diplomacy itself: what happens when a host nation fails to protect a foreign embassy on its soil? The Vienna Convention provides the legal framework, but enforcement depends on political will.

The legal process moved through the Iranian courts. On May 21, 2025, Yasin Hosseinzadeh was executed. The sentence answered Aliyev's demand for the perpetrator to face the full extent of the law. But the deeper questions the attack raised about Iran-Azerbaijan relations, about the security of diplomatic missions in Tehran, about the competing narratives of personal grievance versus state-sponsored violence, remained unresolved. The embassy compound on its Tehran street sits quiet now. The bullet holes have been repaired. The diplomatic staff eventually returned. But the morning of January 27, 2023, left a scar on the relationship between two nations that share a border, a history, and a mutual wariness that the attack only deepened.