In a significant ruling, Iran executed Yasin Hosseinzadeh, convicted of the murder of the head of security at the Azerbaijani Embassy in Tehran during a deadly attack in 2023. The execution, announced by the Iranian judiciary's Mizan news outlet, deepens tensions between the two neighboring countries. While Iran characterized the attack as stemming from personal grievances, Azerbaijan’s President Ilham Aliyev condemned it as a terrorist act.

Hosseinzadeh's conviction followed claims in court where he explained that he had entered the embassy armed with an AK-47, believing his estranged wife was inside and refusing to see him. The Iranian supreme court upheld his death sentence earlier this year, highlighting the severity of the incident that strained diplomatic ties.

The historical relationship between Iran and Azerbaijan has been characterized by mutual distrust, stemming from Azerbaijan's alignment with Turkey and its connections to Israel, along with Iran's support of Armenia in regional conflicts. However, in a potential sign of warming relations, Iranian President Masoud Pezeshkian visited Aliyev recently, affirming improved diplomatic ties.

In response to the 2023 attack, Azerbaijan closed its Tehran embassy and withdrew its diplomatic personnel. The embassy subsequently reopened last year in a newly secured location, but details regarding the attack remained largely unaddressed in official statements. In a further indication of strengthened cooperation, Iranian and Azerbaijani militaries conducted joint exercises this week, suggesting a desire to move past the violence and towards a more stable relationship.