The European Union has suspended a travel ban against Iranian Foreign Minister Ali Akbar Salehi, a former head of Tehran's nuclear energy agency, an EU spokeswoman said on Thursday.

"He is suspended from the travel ban because of his new role as foreign minister," said Maja Kocijancic, spokeswoman for EU foreign policy chief Catherine Asthon.

Salehi, who became acting foreign minister in December and officially took charge as chief diplomat in February, had been forbidden on EU soil for his role in his country's nuclear activities.

The decision to suspend the travel ban was taken by EU foreign ministers on Monday even as they expanded sanctions on the Islamic republic by adding more than 100 firms to a blacklist of companies hit by an assets freeze.

Ashton is seeking to revive international talks with Iran over a nuclear programme that the West suspects serves as a cover to build an atomic bomb.

The EU and the United States have slapped unilateral sanctions on Iran on top of punitive measures imposed by the United Nations over Tehran's refusal to halt nuclear activities.

Iran denies the charge and insists it is merely trying to produce civilian energy.