VIENNA, (AFP) — A high-level UN nuclear agency delegation will visit Iran late this month to try to clear up claims of covert weapons activities that have stoked tensions between Tehran and the West, diplomats said Friday.

The trip led by International Atomic Energy Agency chief inspector Herman Nackaerts and the agency’s number two Rafael Grossi would last from January 28 through the first week of February, one Western diplomat told AFP.

Another envoy also said the visit, two months after an IAEA report on Iran took suspicions to a new level that Tehran is developing nuclear weapons, would “likely” be from January 28, although it was not yet definite.

There was also some “ambiguity” on whether the delegation would merely be able to hold talks with Iranian officials or whether they will be able to visit sites covered in the IAEA’s November 8 report, the second diplomat said.

“It may be that the Iranians just want a short discussion in Tehran, which would not be what the IAEA is looking for,” the envoy told AFP on condition of anonymity.

An IAEA spokesman declined to comment. Iran’s ambassador, Ali Ashgar Soltanieh, who said in December he would hold talks with the IAEA in Vienna this month about a visit, was not immediately available to say any more.

The delegation would include alongside the Belgian Nakaerts and the Argentine Grossi — the righthand man of IAEA chief Yukiya Amano — the body’s senior legal official Peri Lynne Johnson, a United States citizen, envoys said.

“The aim of this mission is to try to get answers once and for all to all the questions raised by the IAEA’s report in November,” the first diplomat told AFP, without wishing to be identified.

Iran denies seeking atomic weapons, saying its programme is peaceful, but Western countries strongly suspect otherwise and the UN Security Council has slapped four rounds of sanctions on the Islamic republic.

Ali Larijani, the influential speaker of Iran’s parliament, said Thursday during a visit to Turkey that his country stood ready for negotiations with the five permanent members of the UN Security Council, plus Germany.

In its November 8 report, rejected as “baseless” by Iran, the IAEA had said it was able to build an overall impression that Tehran “carried out activities relevant to the development of a nuclear explosive device.”

The analysis was based on what the agency called broadly “credible” intelligence provided by several unnamed countries, as well as its own information.

The evidence included a bus-sized steel container visible by satellite for explosives testing and weapons design work, including examining how to arm a Shahab-3 missile, capable of reaching Israel, with a nuclear warhead.

Since the publication of the report, Western countries have sought to increase pressure on Iran, with the United States and the European Union taking aim at Iran’s oil industry and its central bank.

Tensions have also been stoked by Iran showing off what it said was a CIA drone it captured using cyberwarfare, while in October Washington alleged Iranian involvement in a suspected plot to assassinate the Saudi ambassador to the US.

Iran, where a judge on Monday reportedly sentenced to death a US-Iranian former Marine for “membership of the CIA”, has also threatened to close the Strait of Hormuz, a chokepoint for 20 percent of the world’s oil.

Also on Monday the IAEA said that Iran had starting enriching uranium to purities approaching that needed for a nuclear weapon inside a mountain bunker at Fordo near the holy city of Qom.

Iran says the 20-percent enriched uranium is for medical purposes but Washington called it “a further escalation of their ongoing violations with regard to their nuclear obligations.”

On Wednesday meanwhile Mostafa Ahmadi Roshan, a deputy director of Iran’s main uranium enrichment plant, died in a car bomb blast that Tehran blamed on the US and Israeli intelligence services.

The attack was similar to four others in Tehran over the past two years targeting Iranian scientists, three of which succeeded. In the fourth, the scientist — who now heads Iran’s atomic energy organisation — escaped.