A Navy amphibious ship with several hundred Marines aboard is now operating in the eastern Mediterranean near five destroyers that could soon launch Tomahawk missiles at Syria.

However, the amphibious ship USS San Antonio is not part of any of the U.S. military planning for a limited strike against Syria, according to defense officials who said Friday that it had been ordered to remain in place as part of "prudent planning."

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.

It transited through the Suez Canal on Thursday from the Red Sea and is headed for a port call at the U.S. naval base at Souta Bay on the Greek island of Crete.

But it received new orders Friday to remain in place, though without a specific tasking. "It's being kept in the area as a prudent decision should the ship's capabilities be required," said a defense official.

Though not involved in the planning for a possible limited U.S. military action against Syria, 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.

That scenario played out in the early days of the 2011 air assault on Libya when Marines from the 26 th MEU aboard the amphibious ship USS Kearsarge rescued one of two F-15 pilots forced to eject after their fighter crashed outside Benghazi.

For now, U.S. officials said any limited U.S. military action against Syria will likely come in the form of Tomahawk cruise missiles fired from Navy destroyers currently stationed in the eastern Mediterranean.

There are now five U.S. destroyers in the waters of the eastern Mediterranean, but even those numbers are the result of fortuitous timing. Typically, three Navy destroyers are stationed there to counter an Iranian ballistic missile threat to Europe. Two of the destroyers were held over at the end of their deployments because of the dynamic situation in Syria and are now serving alongside the two destroyers that were slated to replace them.

The San Antonio is one of three ships, carrying the 2,200 Marines of the 26th MEU aboard, that have been serving a six-month deployment to U.S. Central Command's area of operations. That area encompasses the Middle East area around the Arabian Peninsula.

The three-ship force is headed by the amphibious assault ship USS Kearsarge, which is currently in the Persian Gulf. The other ship in the task force is the USS Carter Hall, which is currently off the Seychelles in the Indian Ocean.

One official acknowledged that the ship's original movement to the Mediterranean was purely coincidental given the possibility of a limited U.S. military action against Syria. Another official explained that the ship's entry into the Mediterranean was planned when it set out to sea in March. The official said the ship will come under U.S. Africa Command's control for security cooperation efforts with regional partners.

The San Antonio will remain in the Mediterranean for the duration of its deployment, which ends in late October according to another official.