European Union foreign policy chief Javier Solana says he has had "constructive" talks with a top Iranian negotiator on the dispute over Iran's nuclear program.
Solana says he hopes they can meet again in three weeks. He spoke after four hours of talks with Iran's Ali Larijani in Lisbon on Saturday.
Larijani said Iran wants to settle the nuclear dispute through diplomacy.
Members of the UN Security Council are discussing additional sanctions against Iran for its refusal to suspend uranium enrichment, a process that can be used to build nuclear weapons.
The council has already imposed two rounds of limited sanctions on Iran.
Diplomats say new sanctions under discussion include tighter travel bans on Iranian officials, freezing assets of Iranian banks, and inspecting Iranian shipping.
The United States and its allies accuse Iran of trying to develop nuclear weapons. Iran says its nuclear program is for the peaceful production of energy.