Iran could agree to lower the level of its highly enriched uranium if all sanctions are lifted, the country's atomic chief said, Reuters reported.

Iran's offer is seen as a clear indication of its position in ongoing negotiations with the United States.

Fears of war between Washington and Tehran have been high since US President Donald Trump deployed naval forces to the Middle East. US and Iranian diplomats have been holding talks in Oman since last week, led by Omani mediators, amid heightened tensions.

The United Nations' nuclear agency estimated last year that Iran has stockpiled more than 400 kilograms of enriched uranium, which it said was up to 60 percent enriched.

The uranium is said to have reached weapons-grade purity of 90%, and Iran's stockpile is only one step away from reaching that level, the institute said.

The United States, which carried out airstrikes on Iran's nuclear facilities last year, wants it to give up this uranium stockpile.

"The option of diluting 60 percent enriched uranium depends on whether all the sanctions imposed on us in return are lifted or not," said Mohammad Eslami, head of Iran's Atomic Energy Organization.

The official said that the idea of exporting Iran's enriched uranium to another country has not been raised in talks with US officials so far, according to the Iranian news agency ISNA.

Meanwhile, Ali Larijani, a close advisor to Iran's Supreme Leader Ayatollah Ali Khamenei and secretary of the National Security Council, is reportedly traveling to Oman, where negotiations with the United States are underway.