Chalabi, who has been improving his relations with Washington after falling out with the U.S. administration, was appointed acting oil minister after the incumbent Ibrahim Bahr al-Uloum was given leave, the officials said.

Uloum told Reuters he was "intent on resigning". Aides to Chalabi confirmed that he had been appointed acting oil minister.

A ministry spokesman allied to Uloum said the country was facing what he called an impending oil supply crisis. "Production in the north, centre and south is about to suffocate," he said.