President Donald Trump's administration has sought to cut off all exports from Iran but has twice granted three-month exemptions to Iraq, mindful of chronic blackouts that have reignited unrest in the war-torn country.

"Hopefully this waiver will be extended until Iraq can stand on its feet economically," Speaker Mohammed al-Halbusi said at the US Institute of Peace on a visit to Washington, where he met leaders including Vice President Mike Pence.

Halbusi, a member of the Sunni minority whose bloc is nonetheless considered sympathetic to Shiite power Iran, said Iraq imported 30 percent of its power despite its plentiful oil reserves and needed about three years to develop its own capacity.

"After these three years, maybe we can see Iraq as economically independent and we won't need to import power or electricity from a foreign country. Maybe we can address this issue after three years," he said.

Speaking afterwards to reporters, Halbusi warned the United States of the negative effect of "any hasty, uncalculated step to adopt policies and procedures against countries in this region."

Trump last year exited an international agreement on curbing Iran's nuclear program and reimposed punishing sanctions with hopes of curbing the clerical regime's influence around the Middle East.

Secretary of State Mike Pompeo, meeting Thursday with Halbusi, said he supported an Iraq "open to the region and the world" and pledged US help for the country's development, according to a State Department statement that did not mention Iran.