WASHINGTON - PRESIDENT-ELECT Barack Obama has hired veteran Democrats Sam Nunn and Warren Christopher to head his transition teams at the Pentagon and State Department, senior government officials and others said on Tuesday.

Mr Nunn is a former Georgia senator who was chairman of the Senate Armed Services Committee. He was once rumoured as a potential running mate for Mr Obama this year. Mr Christopher was President Bill Clinton's first secretary of state.

They are part of a national security brain trust for Mr Obama that is heavy on former Clinton administration officials, including possible national security adviser James Steinberg, a former State Department official.

Mr Obama's national security transition offices will work with the outgoing Bush administration to hand off management of two wars and complex diplomacy with North Korea, Russia and other nations.

Mr Obama has not announced his choices to be defense secretary and secretary of state.

Mr Nunn will lead a large transition office at the Pentagon that also includes former Clinton Navy secretary Richard Danzig and former Clinton-era Pentagon comptroller Bill Lynn, officials said.

They spoke on condition of because the Obama transition office has not announced the names. The announcements are expected later this week.

Clinton Pentagon officials turned think tankers Michele Flournoy and Kurt Campbell are part of the Obama transition office at the Pentagon. Clinton-era State Department officials Wendy Sherman and Tom Donilon are helping out at State. -- AP