Iran has lodged a complaint to the United Nations regarding US accusations that it tried to assassinate the Saudi ambassador in Washington.

Iran's Foreign Minister Ali Akbar Salehi said on Saturday that one of the alleged plotters the US calls an Iranian military official, is really a member of the People's Mujahideen Organisation of Iran.

That group is recognised as a terrorist group both by Tehran and Washington.

Salehi also says the plot is part of a multi-pronged U.S. strategy to smear Tehran, a process he says will continue next week when the U.N. nuclear agency publishes a report, claiming new evidence about Iran's nuclear program.