European Union foreign policy chief Javier Solana says talks with Iran's top nuclear envoy Ali Larijani have been constructive. The two met for four hours in Lisbon to discuss Tehran's contentious nuclear programme.

Mr Larijani says the meeting with Mr Solana was positive but warned that further UN sanctions could derail further settlement negotiations.

The UN Security Council is discussing a third set of sanctions against Iran over concerns it is covertly trying to build nuclear weapons. Iran says it needs nuclear power to generate electricity and export more of its oil and gas.

Mr Solana hopes for another round of talks in three weeks.