Iran's hardliner President Ebrahim Raisi has vowed revenge for the killing of Qasem Soleimani in 2020 unless former US President Donald Trump is put on trial.

"If Trump and (former Secretary of State Mike) Pompeo are not tried in a fair court for the criminal act of assassinating General Soleimani, Muslims will take our martyr's revenge," Raisi said in a televised speech on Monday.

Iran’s Supreme Leader Ali Khamenei also vowed revenge in a speech on January 1, saying, “Trump and others like him will be forgotten and lost in the dustbin of history, of course after paying for their crimes in the world.”

Soleimani, who was Iran’s top military and intelligence operator outside its borders, was in charge of supporting and organizing militant proxy forces, including the Lebanese Hezbollah and Iraq Shiite militia groups that have repeatedly attacked US forces. He was killed by a US drone strike in Baghdad airport in January 2020.

Iran is engaged in indirect talks with the United States to restore the 2015 nuclear agreement abandoned by Trump in 2018. Critics say that restoring restrictions on Tehran’s nuclear program is not sufficient and sanctions should continue until it is willing to limit its ballistic missile program and alter its regional policies.