Foreign diplomats tour Iran nuclear sites
A group of foreign diplomats is touring some of Iran's nuclear sites, as Tehran seeks to build support for its controversial nuclear programme.
Iran said it was a gesture of goodwill and transparency, but the US was not invited - while China, Russia and the EU refused the invitation.
Tehran said its uranium enrichment programme was progressing "strongly".
It was responding to US claims that the programme was being hit by international sanctions.
On Saturday, ambassadors from Algeria, Cuba, Egypt, Oman, Syria, Venezuela and the Arab League visited an unfinished heavy water reactor at Arak.
On Sunday, the diplomats are expected to tour an enrichment facility at Natanz.
"No country in the world will show its nuclear installations to others, and this is a sign that Iran's nuclear activities are peaceful," said Ali Akbar Salehi, head of Iran's Atomic Energy Organisation.
But Mr Salehi also stressed that "the recent sanctions did not create any problems for our nuclear activities".
"Our activities, especially in (uranium) enrichment, are also continuing very strongly. The production of enriched uranium is growing," he said.
Mr Salehi was responding to a recent comment by US Secretary of State Hillary Clinton that Iran's nuclear programme was being hampered by the international sanctions.
The tour of Iran's nuclear sites comes ahead of the resumption of UN talks about Iran's controversial nuclear programme.
But the EU earlier said the tour could not replace visits by nuclear inspectors.
Russia and China indicated their diplomats would not be taking part while the EU said it was up to officials from the International Atomic Energy Organisation Agency (IAEA) to inspect the facilities.
The US called the tour a ploy.
The BBC's Iran correspondent James Reynolds says it is unlikely that the event will change many people's minds about the nature of Iran's nuclear programme.
Western nations suspect that Iran is attempting to build nuclear weapons, but Tehran says its nuclear programme is for peaceful civilian purposes.
Diplomats who are not nuclear scientists or weapons inspectors will be unable to give a definitive answer one way or the other, our correspondent adds.