TEHRAN - Mohammad Javad Zarif has said Iran's diplomacy is being "poisoned" by party and factional fighting, a day after he offered to resign as foreign minister.

He made the comments in a newspaper interview that took place before he announced he was stepping down, apologising for all his "shortcomings".

Hardliners in Iran have long criticised Mr Zarif over his role in negotiating a nuclear deal with world powers in 2015.

President Hassan Rouhani has yet to formally accept his resignation.

Mr Rouhani made no mention of Mr Zarif's announcement in a televised speech on Tuesday morning, but he did praise him for his "resistance" and "capabilities".

"If our foreign ministry is doing something, it is because it is from the people and it represents the people," the president added. "The government, in general, is elected by the people."

Mr Rouhani also noted that Syrian President Bashar al-Assad had "explicitly thanked" the Iranian foreign ministry for its help during the country's civil war.

Earlier, a majority of MPs signed a letter to the president on Tuesday asking for Mr Zarif to remain in post, a spokesman for parliament's National Security and Foreign Policy told the official Irna news agency.

Mr Zarif announced his resignation on Monday night in an Instagram post that gave no explanation for the decision.

"I apologise for not being able to continue in the post and for all the shortcomings and flaws in the period," he wrote.(FA)