Reports that Iran may assign a diplomatic role in a proposed committee overseeing the implementation of the ceasefire in Lebanon to its ambassador-designate, whom Beirut has refused to accredit, have raised legal and political questions over Lebanon's sovereignty and compliance with international diplomatic law.

The controversy stems from remarks made on June 30 by Iranian Parliament Speaker Mohammad Bagher Ghalibaf, who announced that a joint committee comprising Iran, the United States and Lebanon would be established—with mediation by Qatar and Pakistan—to monitor implementation of arrangements aimed at ending the war in Lebanon.

Following Ghalibaf's announcement, reports circulated that Tehran intends to assign a role on the committee to Mohammad Reza Sheibani, Iran's ambassador-designate to Lebanon.

Lebanon, however, rejected Sheibani's appointment, declared him persona non grata, and did not allow him to present his credentials to President Joseph Aoun. Despite that decision, Sheibani has remained at the Iranian embassy in Beirut, reportedly with the backing of Hezbollah and the Amal Movement, while continuing to challenge the Lebanese state's refusal to recognize him as ambassador.

The issue has received little official follow-up in Lebanon, and neither Beirut nor Tehran has publicly commented on the reports.

Some observers have interpreted Ghalibaf's announcement as an Iranian trial balloon designed to gauge political reactions.

Others argue that, if Tehran proceeds with such a move, it would represent an unprecedented challenge to Lebanon's sovereignty and amount to treating the country as though it were under Iranian tutelage.

Critics say the reported plan would constitute a twofold challenge: one directed at Lebanon as the receiving state, and another aimed at the international legal framework governing diplomatic relations, particularly the 1961 Vienna Convention on Diplomatic Relations.

Former Lebanese ambassador Gaby Soufan, who has held several diplomatic posts, said the reported proposal effectively ignores Lebanon's status as a sovereign state.

"From the standpoint of the receiving state, the Iranian parliament speaker is acting as though Lebanon does not exist," Soufan told Annahar.

He argued that the proposal disregards Lebanon's internationally recognized legal personality as a sovereign state, a founding member of the United Nations and a country that has long played an active diplomatic role.

According to Soufan, the proposal also ignores the Lebanese government's decision declaring Sheibani persona non grata under Article 9 of the Vienna Convention on Diplomatic Relations.

The article gives host countries the right to declare any diplomat unacceptable "at any time and without having to explain its decision," although Lebanon publicly outlined its objections to the ambassador-designate.

Soufan said such decisions are generally based on concerns including misconduct, interference in the host country's internal affairs, actions exceeding the scope of diplomatic duties, or threats to national security.

He argued that if Iran formally assigns Sheibani new responsibilities despite Lebanon's decision, it would amount to a deliberate disregard for international law.

Declaring a diplomat persona non grata, he said, means the host state has withdrawn its confidence and consent for that individual to continue serving in a diplomatic capacity.

Under Article 9 of the Vienna Convention, the sending state—in this case Iran—is required to recall the diplomat or terminate his functions within the diplomatic mission.

According to Soufan, Tehran has so far failed to fulfill those obligations.

The controversy comes as Sheibani is already among individuals targeted by U.S. sanctions.

On May 21, the U.S. Treasury Department's Office of Foreign Assets Control (OFAC) imposed sanctions on nine people in Lebanon, accusing them of obstructing the peace process and efforts to disarm Hezbollah.

Those sanctioned included lawmakers, security and military officials accused of preserving Hezbollah's influence within Lebanese state institutions.

The sanctions also targeted Sheibani, along with security officials affiliated with the Amal Movement led by Parliament Speaker Nabih Berri.