In the no-bid contracts, the administration said it had provided what it called purely technical help, in writing the contracts. The US played no role in choosing the companies, the administration has said.

Disclosure of those contracts has provided substantial fuel to critics of the Iraq war, both in the US and abroad, who contend that the enormous Iraqi oil reserves were a motivation for the American-led invasion — an assertion the administration has repeatedly denied.

Iraq’s oil minister, Hussain al-Shahristani, has condemned the Kurdistan deal as illegal because it was not approved by Iraq’s Central Government and was struck without an oil law, which has still not been passed. After the deal was signed last year, a senior State Department official in Baghdad criticised it, saying, “We believe these contracts have needlessly elevated tensions between the KRG and the national Government of Iraq.”

The State Department said Wednesday that it had discouraged the deal. Hunt officials declined to comment, and Kurdish government officials said there was no impropriety.