A group of American advisers led by a small State Department team played an integral part in drawing up contracts between the Iraqi government and five major Western oil companies to develop some of the largest fields in Iraq, American officials say.

The disclosure, coming on the eve of the contracts’ announcement, is the first confirmation of direct involvement by the Bush administration in deals to open Iraq’s oil to commercial development and is likely to stoke criticism.

In their role as advisers to the Iraqi Oil Ministry, American government lawyers and private-sector consultants provided template contracts and detailed suggestions on drafting the contracts, advisers and a senior State Department official said.

It is unclear how much influence their work had on the ministry’s decisions.

The advisers  who, along with the diplomatic official, spoke on condition of anonymity  say that their involvement was only to help an understaffed Iraqi ministry with technical and legal details of the contracts and that they in no way helped choose which companies got the deals.