Baghdad ? Iraq’s oil minister on Monday announced the start of bidding by foreign companies for contracts to boost the production of eight underperforming oil and gas fields.

The contracts, to be executed in about 18 months, would open Iraq’s oil fields to foreign companies for the first time since former dictator Saddam Hussein nationalized foreign concessions in the 1970s.

Oil Minister Hussein Shahristani said 35 companies had been selected to bid. Among them were seven from the U.S. and four each from China and Japan.

The bidding will proceed even though parliament has not yet ratified a national oil law to regulate foreign contracts. The measure has been stalled by disagreements over how to divide oil revenues among Iraq’s regions.