Politico.com, ABC News and CNN said the highly regarded Gates would stay at the Pentagon at least for president Obama's first year and execute the Democrat's signature policy of withdrawal from Iraq.

"It is a done deal," ABC cited a source close to the process as saying, and said the formal announcement would be made by Obama's transition team after Thursday's Thanksgiving holiday.

Aides to Obama told AFP they could not immediately confirm the reports.

Politico said Gates would be part of a raft of national security positions announced next week, including former NATO commander General James Jones as national security adviser.

Quoting unidentified officials, it said Susan Rice, a senior foreign policy adviser to Obama, would be nominated as US ambassador to the United Nations and retired Admiral Dennis Blair would become director of national intelligence.

Politico added that former deputy national security adviser James Steinberg would be named deputy to Hillary Clinton as secretary of state, with both diplomatic jobs also to be announced next week.

The selection of Gates, who has won bipartisan praise as a member of President George W. Bush's cabinet, would allow Obama to make good on his pledge of staffing his own cabinet with at least one Republican.

"The appointment has substantial advantages for Obama, who now can keep his pledge of drawing down troops in Iraq with the aid of an architect of the Bush administration's successful troop 'surge' strategy," Politico said.