"The next round of talks between Dr Larijani and Mr Solana will be held in Lisbon on Saturday June 23," IRNA said, quoting a statement by Iran's supreme national security council which is headed by Larijani.

The two men have been holding a series of talks aimed at resolving the crisis over Iran's nuclear programme, which is feared to be a cover for an atomic weapons drive.

Oil-rich Iran denies the allegation, insisting it only wants to make nuclear fuel to meet its growing energy demands.

Iran has been slapped with two sets of UN Security Council sanctions and it is likely to face a third for its refusal to suspend sensitive enrichment work, the process which makes nuclear fuel and the fissile core of an atom bomb.

Solana and Larijani last met on May 31 in Madrid, but no breakthrough was reported.