Iran has submitted a formal complaint to the United Nations Secretary-General and the President of the Security Council against the head of the International Atomic Energy Agency (IAEA), Rafael Grossi, accusing him of bias and negligence amid rising tensions over Iran’s nuclear programme.

The move, reported by Iran’s semi-official Fars News Agency, comes as Tehran intensifies criticism of the nuclear watchdog’s handling of what it describes as “peaceful nuclear activities,” alongside Grossi’s alleged silence over Israeli strikes on Iranian nuclear sites.

Iran’s Permanent Representative to the United Nations, Amir-Saeid Iravani, condemned what he called Grossi’s “politicised” stance. In a letter to the UN, Iravani criticised the IAEA chief for “failing to take a clear position on Israel’s aggressive actions,” particularly its reported attacks on Iranian nuclear facilities, which Tehran argues are a violation of international law.

Mohammad Eslami, the head of Iran’s Atomic Energy Organisation, also announced on Thursday that legal action may be taken against Grossi for his “inaction” in the face of what Iran perceives as threats to its nuclear infrastructure by Israel.

Tensions have escalated since Grossi’s remarks earlier this month, in which he stated that Iran had failed to provide sufficient information about its nuclear activities. "The agency will not be in a position to provide assurance that Iran’s nuclear programme is exclusively peaceful," he warned.

Addressing the UN Security Council on Friday, Grossi further expressed concern over security risks, stating that recent attacks on Iranian nuclear facilities had resulted in a “sharp degradation in nuclear safety and security.”

The standoff comes at a time of heightened regional instability and uncertainty over the future of nuclear diplomacy. Talks to revive the 2015 Iran nuclear deal, known as the Joint Comprehensive Plan of Action (JCPOA), have long stalled, while Iran continues to expand its uranium enrichment programme.

Iran insists that its nuclear programme is intended for civilian purposes, but Western powers and the IAEA have repeatedly expressed doubts, citing lack of transparency and restrictions on inspections.