The US last year reimposed tough sanctions against Iran's energy sector but granted select countries six-month waivers to continue importing oil products from Tehran.

Those exemptions will end in early May, the White House announced on Monday.

US President Donald Trump said that Saudi Arabia and other members of the Organization of the Petroleum Exporting Countries (OPEC) would "more than make up" the resulting difference in the oil supply.

Iraq, the cartel's second-largest producer, has the capacity to increase its crude oil exports, a top government official told AFP on Monday.

"We are ready to export another quarter-million barrels daily. The market's needs will become clearer in the coming days," he said.

The official did not say whether Iraq had already discussed the increase with OPEC or with the United States.

The countries that had received exemptions in November were China, India, Japan, South Korea, Turkey, Italy, Greece and Taiwan.

Iraq received a separate waiver that would allow it to continue importing Iranian gas and electricity, crucial to stop up the widespread power shortages in Iraq.

That initial exemption has been extended twice, and is set to end in June.

Iraq last month exported just under 3.4 million barrels per day, after having agreed last year to trim production alongside other producers so that prices would go up.

Oil prices hit a five-month high earlier this month at more than $70 per barrel.