The latest reports, to be discussed at the International Atomic Energy Agency's board of governors' meeting next week, come as the United States threatened strikes on Iran and pressed its biggest military build-up in the Middle East in decades.

"Technical discussions will take place in Vienna in the week beginning 2 March 2026," the IAEA confirmed.

It urged Iran to cooperate "constructively", stressing "the utmost urgency" of its request to verify all its nuclear material, according to one of the reports.

Considerable uncertainty surrounds the fate of Iran's stockpile of more than 400 kilos of 60-percent enriched uranium that was last seen by nuclear watchdog inspectors last June 10.

Israel launched strikes on Iran last June, beginning a 12-day war that the US briefly joined to bomb Iranian nuclear sites.

Tehran suspended some cooperation with the IAEA and restricted the watchdog's inspectors from accessing sites bombed by Israel and the United States, accusing the UN body of bias and of failing to condemn the strikes.

"The agency's loss of continuity of knowledge over all previously declared nuclear material at affected facilities in Iran needs to be addressed with the utmost urgency," the report said.

Western countries, led by the United States as well as by Israel, Iran's arch-enemy and considered by experts to be the only nuclear power in the Middle East, accuse the Islamic republic of seeking to acquire nuclear weapons.

Tehran denies having such military ambitions, but insists on its right to this technology for civilian purposes.

On Thursday, Oman-mediated talks between Iran and the US in Geneva were seen as a last-ditch bid to avert war, though initial optimism was tempered by Tehran warning Washington must drop "excessive demands" to reach a deal.

Iran had been enriching uranium to 60 percent, well above the 3.67 percent limit allowed by the now-defunct 2015 nuclear agreement and close to 90 percent needed to make a bomb, according to the International Atomic Energy Agency.