European foreign ministers formally adopted the new measures July 26 on the oil and gas industries, going beyond a fourth set of UN sanctions imposed over Iran's refusal to freeze uranium enrichment. Canada then followed suit.

The moves, which follow similar sanctions imposed by the United States, are aimed at reviving moribund talks between Iran and six world powers - Britain, China, France, Germany, Russia and the United States.

"Today we sent out a powerful message to Iran, and the message is that their nuclear programme is a cause of serious and growing concern to us," EU foreign affairs chief Catherine Ashton told reporters.

"But our objective remains, as I have always said, to persuade Iranian leaders that their interest is served by a return to the table. Sanctions are not an end in themselves," she said.

Iran's foreign ministry however said the sanctions were not "an effective tool" and would only serve to "complicate" its showdown with the West.

AFP