About 1,000 Marines from Okinawa were headed to the Philippines Friday to aid in the super Typhoon Haiyan disaster that has left hundreds of thousands desperately searching for food, water and shelter.

A week after Haiyan slammed into the central Philippines with gusts in excess of 200 mph, the National Disaster Risk Reduction and Management Council in Manila put the death toll at 3,631, while the United Nations said at least 4,460 had died.

Filipino officials said 12,487 had been injured and 1,187 were listed as missing, while the Red Cross said the number of missing could be as many as 25,000.

Marine Forces Pacific said that 900 Marines from the 31st Marine Expeditionary Unit (MEU) on Okinawa were headed to the Philippines aboard the Navy amphibious ships Germantown and Ashland, and should arrive early next week. Another 100 Marines from the 31st MEU were going to the Philippines by C-130 cargo aircraft.

The additional Marines would join 400 from the 3rd Marine Expeditionary Brigade already on the ground under the command of Brig. Gen. Paul Kennedy.

The Germantown and the Ashland were bringing heavy engineering equipment, including back hoes and dump trucks, and Amphibious Assault Vehicles (AAVs) capable of operating in water and overland. The two amphibious ships were joining a growing U.S. armada in the Philippines that includes the carrier George Washington and its strike group.

To oversee the effort, the U.S. Pacific Command has established a joint task force to coordinate Defense Department operations in the Philippines. Joint Task Force 505 will be commanded by Marine Lt. Gen. John E. Wissler, who will go from Okinawa to the Philippines to take command. Wissler will report directly to Navy Adm. Samuel L. Locklear III, head of the Pacific Command.

The U.S. has thus far contributed $22 million in humanitarian assistance in addition to the growing military presence for a HADR (Humanitarian Assistance/Disaster Relief) effort dubbed Operation Damayan that was becoming a test case for the U.S. strategic shift of forces to the Pacific.

The U.S. effort was in marked contrast to that of Chin , whose own naval buildup was aimed at wresting influence from the U.S. in the region. China’s initial offer of $100,000 in aid was mocked, even by the official Chinese media, and Beijing has now pledged to commit about $1.6 million.

Aid groups have been raising the alarm about the possibility of the outbreak of a range of diseases that thrive in tropical climates.

"The population is at increased risk of tetanus as well as outbreaks of acute respiratory infections, measles, leptospirosis and typhoid fever," the United Nations Office for the Coordination of Humanitarian Affairs said.