US Defence Secretary Donald Rumsfeld has ordered another 27,000 US troops to head for the Gulf.
It comes a day after more than 35,000 US soldiers were told they were being shipped out for possible war with Iraq.
Officials say the units designated for deployment in the latest order include a squadron of Air Force F-117 stealth fighter-bombers.
The F-117s, based at Holloman Air Force Base, New Mexico, played a key role in the 1991 Gulf War.
The order also includes thousands of marines and an army airborne infantry brigade.
The troops' actual departure for the potential war zone will be spread out over the rest of January.
Central Command, the headquarters that would run any war against Iraq, has begun dispatching its battle staff to a command post in Qatar, and it is expected to be operational near the end of January.
The Navy has two aircraft carriers within striking distance of Iraq, plus two others ready to join them on short notice. A fifth carrier, the USS Kitty Hawk, has received an order to prepare to deploy to the Gulf region from its homeport in Japan, Navy officials said this week.
AP