By the end of the month UN inspectors will visit the Arak plant, But Natanz will have atomic capabilities within a year.

Iran has agreed to let UN inspectors visit a heavy water reactor by the end of the month as part of a series of measures aimed at clearing up questions over Tehran's nuclear work, the UN atomic agency said yesterday. Iran confirmed it would provide access to the reactor being built at Arak, which will have the capacity to produce plutonium.

Iran has blocked access to Arak since April, in an escalating crisis over its nuclear activities that some fear could lead to US or Israeli military strikes against Iranian facilities.

A diplomat close to the agency said of the announcement “as long as the things promised are executed, it is a good deal, it is significant”. Iran's ambassador to the IAEA, Ali Asghar Soltanieh, said the inspection of the reactor at Arak would “take place soon” and added that “just one visit will be enough”. He also announced that Iran and the agency would hold fresh talks in Vienna on July 25 and 26.

Nevertheless, some experts say Iran had been expected to have, by the end of this month, 3,000 centrifuges running in Natanz - sufficient to produce enough enriched uranium for one atom bomb in less than a year.

• Iran