US President-elect Barack Obama vowed Monday to ensure the US military remains the strongest force "on the planet" despite the economic challenges facing the country.

"To ensure prosperity here at home and peace abroad, we all share the belief we have to maintain the strongest military on the planet," Obama said as he unveiled a heavyweight national security team to serve when he takes office on January 20.

"We also agree the strength of our military has to be combined with the wisdom and force of diplomacy, and that we are going to be committed to rebuilding and restrengthening alliances around the world to advance American interests and American security," he said.

Obama was speaking after nominating former first lady Senator Hillary Clinton to be his secretary of state and announcing that Defense Secretary Robert Gates would remain as defense secrtary.

Pentagon to reserve 20,000 troops for domestic emergencies: report
The US Department of Defense plans to deploy 20,000 troops nationwide by 2011 to help state and local officials respond to terror or nuclear attacks and emergencies, The Washington Post said Monday.

Citing Pentagon officials, the newspaper said the plan calls for three rapid-reaction forces.

The first 4,700-strong unit, built around an active-duty combat brigade, is based at Fort Stewart, Georgia, and is already available for deployment, according to General Victor Renuart, commander of the US Northern Command, it said.

Two additional groups will later join nearly 80 smaller National Guard and reserve units made up of about 6,000 troops to support local and state authorities nationwide, The Post said.

They will all would be trained to respond to domestic chemical, biological, radiological, nuclear, or high-yield explosive attacks.

The newpaper said that civil liberties groups and libertarians had expressed concern that the plan could undermine the Posse Comitatus Act, a 130-year-old law restricting the military's role in domestic law enforcement.