Two amphibious assault ships and five other vessels carrying about 10,000 Marines and sailors left San Diego on Friday for the Persian Gulf region in case of a war with Iraq, the Navy said.
The amphibious assault ships Boxer and Bonhomme Richard were joined by the amphibious transport docks Cleveland and Dubuque and the dock landing ships Anchorage, Comstock and Pearl Harbor.
Hundreds of family members and well-wishers turned out in San Diego to say goodbye.
The seven ships carried about 5,000 Marines from Camp Pendleton and about 5,000 sailors, said Cmdr. Jacquie Yost, a spokeswoman for the Navy's 3rd Fleet.
She said the deployment of elements of the 1st Marine Expeditionary Force "has gone smoothly so far."
Many reservists were deployed with regular troops, and other reservists have been ordered to help run Pendleton, Miramar Marine Corps Air Station and Marine Corps Air Station Yuma in Arizona in place of the departing troops, Marine Forces Reserve spokesman Capt. Jeff Pool said this week.
The voyage to the region is expected to last "about a month," Yost said. "At this point in time, we don't know what the end date for the deployment is."
The ships that left Friday are the latest U.S. vessels to head to the Gulf as the United States assembles a large naval force to complement the tens of thousands of ground troops already in place in the region as part of President Bush's buildup for a possible war with Iraq.
The Boxer and Bonhomme Richard resemble aircraft carriers and carry Marines and helicopters for land invasions.
The United States already has two aircraft carrier battle groups in the region, with others placed on alert for possible deployment. In addition, the hospital ship Comfort is sailing toward the region to treat casualties if there is a war with Iraq.
Bush has said the United States will lead a coalition of nations to disarm Iraq by force if Baghdad fails to eliminate its suspected banned weapons programs.