The head of the Organisation of Petroleum Exporting Countries (OPEC) said on Wednesday he hoped the EU would not press sanctions on Iran's "difficult to replace" oil exports.

"I really hope there will not be an EU embargo on Iranian oil," OPEC Secretary General Abdullah El-Badri said at the World Petroleum Congress in Doha.

"It will be very, very difficult to replace" the exports of this OPEC member, he said.

"Europe now is facing some difficulties... so to cut these 865,000 barrels a day immediately, I think it will be a problem," he said, apparently referring to Iran's exports to all of Europe, as the EU imports only around 450,000 bpd from Iran, according to the International Energy Agency.

The EU last week piled up pressure on Tehran following an attack on the British embassy, beefing up sanctions over Iran's nuclear programme, while it threatened to hit its oil and finance sectors next.

EU foreign ministers meeting in Brussels slapped sanctions on an extra 143 firms and 37 individuals, after the publication last month of a report on Iran's nuclear sector by the International Atomic Energy Agency (IAEA).

The ministers threatened in a statement to "extend the scope" of punitive action to strike at Tehran's economic heart.

It said the EU would examine measures targeting the financial system, energy and transport by late January.