WASHINGTON, Nov 20: Up to 1,600 US Marines are preparing to join US commandos in Afghanistan as early as this week in a final drive to hunt down Saudi-born Islamic militant Osama bin Laden, USA Today reported on Tuesday.

The USS Bataan, a Marine amphibious assault ship, joined the USS Peleliu this weekend in the Arabian Sea, each carrying 600 to 800 Marine infantry troops trained for commando operations, the newspaper said on its Web site, citing a US defense official.

The Marines were ready to join Special Operations forces in the fight in Afghanistan in what would be the largest buildup of US forces in Afghanistan, the newspaper said.

Pentagon spokeswoman Victoria Clark was quoted as saying the defense department would not comment on troop movements. But defense officials disclosed on Monday that the Marines sent vertical-takeoff Harrier jets into combat on Sunday from the Peleliu, USA Today reported.

Afghan tribal chiefs were already conducting cave-by-cave searches in the hunt for Osama.

As many as 500 US Special Operations forces have begun blowing up bridges, setting roadblocks and watching borders to prevent Osama and his Al Qaeda forces from leaving the country, the newspaper said.

The Marines could take the pursuit to a new level, forming large assault teams to back up commandos now on the hunt, former Special Operations officer Michael Vickers informed the newspaper.—Reuters