Iran's foreign minister on Monday urged action at the United Nations against US unilateralism as he denounced Washington over wars waged since 2001.

Iranian Foreign Minister Mohammad Javad Zarif addressed the General Assembly for a high-level session to mark the 75th anniversary of the world body, where the United States has been seeking to raise pressure on Iran. 

"The eight violent wars that the United States initiated or joined since 2001, under the rubric of war on terror, have resulted in the loss of hundreds of thousands of innocent lives, countless broken societies and families ... and unprecedented extremism," Zarif said in a video address.

"It's time to change that, saving American blood and treasure, and sparing the world from further misery," he said.

"Our United Nations, at 75, needs to recommit itself to stand up united against unilateralism and war."

Iran quietly backed the United States after the September 11, 2001 attacks in ousting the extremist Taliban regime from Afghanistan but relations quickly deteriorated.

President Donald Trump's administration has imposed sweeping unilateral sanctions on Iran, hoping to end the clerical regime's backing of paramilitary groups in the region.

In recent months, however, the Trump administration failed to persuade the Security Council to extend an arms embargo on Iran and faced doubts even from close allies as it argued that Washington can trigger UN sanctions against Tehran.

The virtual summit for the 75th anniversary of the United Nations opened on September 21 but, with many nations defying guidelines to keep their addresses under three minutes, it was halted with the rest of the speeches taking place Monday.

Most of Monday's addresses were previously recorded and not updated over the past month, according to UN sources.