US President Donald Trump has said that Iran has been asking if US sanctions against the country can be lifted.

"Iran has been asking if the sanctions could be lifted. Iran has got very heavy US sanctions, and it makes it really hard for them to do what they'd like to be able to do. And I'm open to hearing that, and we'll see what happens, but I would be open to it," Trump told reporters late on Thursday at the White House.

Iran's mission to the United Nations in New York did not immediately respond to a request for comment.

Iran's Supreme Leader Ayatollah Ali Khamenei said on Monday that cooperation between Iran and the United States is not possible as long as Washington continues to support Israel, maintain military bases, and interfere in the Middle East.

After taking office for his second term in January, Trump restored his "maximum pressure" campaign on Iran, which includes efforts to prevent Tehran from developing a nuclear weapon.

In June, the US bombed Iran's nuclear sites.

The two countries have held five rounds of nuclear talks before a 12-day war between Iran and Israel in June, but the negotiations have faced major obstacles, including the issue of uranium enrichment on Iranian soil.

Western powers want Tehran to halt enrichment entirely to eliminate the risk of weaponisation — a proposal Iran has rejected.