Iranian state television says diplomats have toured the country's main uranium enrichment facility. Tehran hopes the visit will bolster its assurances that its nuclear work is entirely peaceful.
Iran is trying to build support ahead of more talks with world powers on its disputed atomic program in Istanbul, Turkey, this month. However, the only two participants in those talks to be invited for the weekend tour — China and Russia — turned Tehran down.
The European Union also rejected the invitation, saying it was up to U.N. nuclear inspectors to determine whether Iran's program has a military dimension.
Sunday's visit to the enrichment site at Natanz came a day after the diplomats from seven developing nations toured a plutonium-producing heavy water reactor at Arak.