WASHINGTON: Iran is ringing two deeply buried tunnel complexes with a massive security perimeter linked to its main nuclear complex, a report said on Wednesday, amid US and Israelithreats ofattack.

The Institute for Science and InternationalSecurityreleased its report based on recent satellite imagery as the US and Iran prepare to hold a third round of talks this weekend on a possible deal to reimpose restraints on Tehran`s uranium enrichment programme.

US President Donald Trump, who pulled the US out of a 2015 pact designed to prevent Tehran from developing nuclear weapons, has threatened to bomb Iran unless a deal is quickly reached that would ensure that same goal. Trump`s withdrawal prompted Iran to breach many of the pact`s restraints. Western powers suspect it is pursuing the capability to assemble a nuclear weapon through enrichment of uranium to high fissile purity, which Tehran denies.

David Albright, the institute president, said the new perimeter suggested that the tunnel complexes, under construction beneath Mount Kolang Gaz La for several years, could become operational relatively soon.

Tehran has barred access to the tunnels toinspectors ofthe UN International Atomic Energy Agency(IAEA)who are monitoring its nuclear programme. The head of the UN nuclear watchdog agency called on Wednesday on Iran to explain tunnels built around its Natanz nuclear site, while voicing hope over ongoing US-Iran talks.`I`ve been raising this issue repeatedly, and I will continue to do so,` Rafael Grossi, director generalof the International Atomic Energy Agency (IA E A), told reporters on a visit to Washington.

Grossi, who visited Tehran last week, said that all coun-tries need to inform the IAEA of intentions for facilities around nuclear sites but that Iran has a stance `unique in the world` that it does not need to inform the agency ahead of time. `We`re asking them, what is this for? They are telling us, it`s none of your business,Grossi said.

Grossi said it `cannot be excluded` that the tunnels would store undeclared material but said he did not want to speculate on intentions. `Iran does not have nuclear weapons.

This is very clear. We cannot confuse people. Iran has conducted in the past certain activities that were relevant could be relevant in the process of developing nuclear weapons, he said.

Iranian Foreign Minister Abbas Araqchi, the chief negotiator with the US, said in a post on X in apparent response to the new report that Israel and unnamed `Special Interest groups` were looking to `derail diplomacy.` Iran has said that advanced centrifuges would be assembled in one complex in place of a facility at the nearby Natanz plant, the centrepiece of its nuclear programme, destroyed by sabotage in 2020.

The complexes, Albright said, are being built at depths much greater than Iran`s deeply buried uranium enrichment facility at Fordow, near the holy city of Qom. Iran`s nuclear energy chief Mohammad Eslami, referring to concerns about the vulnerability of its nuclear programme, on Tuesday appeared to refer to projects such as the construction of the new security perimeter around the tunnel complexes.

Meeting with Chinese FM China supports Iran holding talks on its nuclear program with the United States and opposes the use of force and`illegal` unilateral sanctions to try to resolve the issue, Chinese Foreign Minister Wang Yi told Iran`s foreign minister on Wednesday.

Beijing is willing to deepen coordination and cooperation with Tehran on international and regional affairs, Wang told Iran`s Abbas Araqchi during talks in the Chinese capital, according to a ministry statement. `The Chinese side commends Iran`s promise not to develop nuclear weapons and respects Iran`s right to utilise nuclear energy peacefully, Wang said.

The meeting came ahead of further US-Iran nuclear talks this Saturday and after Washington imposed sanctions on some Chinese refiners for buying Iranian oil in recent weeks. The Iranian foreign ministry said on Wednesday that Araqchi had informed his Chinese counterpart of the latest situation of the `indirect talks between Iran and the US` and thanked China for its productive stance on Iran`s nuclear programme and the lifting of sanctions.

China buys some 90 per cent of Iran`s oil exports, traders and analysts have said. The two countries have built a trading system that uses mostly Chinese yuan and a network of middlemen, avoiding the dollar and exposure to US regulators.

Wang and Araqchi also discussed US tariffs during Wednesday`s meeting. `The US`s abuse of tariffs has completely lost popularity and isolated itself from the international community,` Wang said.-Agencies