USS Nimitz carrier group taking up position into Red Sea.

USS Nimitz carrier group taking up position into Red Sea.(Reuters).

The USS Nimitz aircraft carrier and four other ships in its strike group moved into the Red Sea early on Monday, U.S. defense officials said, describing the move as "prudent planning" in case the ships are needed for military action against Syria.

The officials said the Nimitz entered the Red Sea around 6 a.m. EDT (1000 GMT), but the strike group had not received any orders to move into the Mediterranean, where five U.S. destroyers and an amphibious ship, the USS San Antonio, remain poised for possible cruise missile strikes against Syria.

Moving the Nimitz into the Red Sea was aimed at putting more U.S. assets in place if they are needed to support what U.S. officials still describe as a limited attack against Syria after it used chemical weapons against civilians.

The nuclear-powered Nimitz is accompanied by the Princeton, a cruiser, and three destroyers - the William P. Lawrence, Stockdale and Shoup, according to the officials.

The destroyers are carrying a combined load of about 200 Tomahawk missiles, but officials say a limited strike on Syria could be accomplished with half that number.

Retired Admiral Gary Roughead, who served as chief of naval operations during the 2011 strikes on Libya, said the Navy's decision to move the carrier into the Red Sea meant it was closer to the "points of tension."

"It's a prudent move that provides for maximum naval flexibility in the region," Roughead, who is now a fellow at Stanford University's Hoover Institution, told Reuters. "It is not unusual to move carriers around in North Arabian Sea and Red Sea as events dictate."
In addition, ABC News says that an amphibious ship "with several hundred Marines aboard" is also parked in the eastern Mediterranean.

On Friday, the USS San Antonio, a Navy amphibious ship with several hundred Marines aboard, was ordered to remain in the eastern Mediterranean though defense officials said it too was not part of the U.S. military planning for a limited strike against Syria. Defense officials described the move as “a prudent decision should the ship’s capabilities be required.

The San Antonio was originally to be in the Mediterranean as part of a long-scheduled commitment to support U.S. Africa Command, several officials said. The ship was on its way to a port call at the U.S naval base at Souda Bay on the Greek Island of Crete when it was ordered to remain in the area.

The San Antonio has resources that could prove useful in future operations in the region. For example, the ship has several hundred Marines aboard from the 26th Marine Expeditionary Unit (MEU), as well as several helicopters or V-22 Ospreys that could be useful in helping to rescue downed pilots.