Washington (CNN) -- The Department of Defense is reducing the number of ships and aircraft it is contributing to Operation Tomodachi, the response to the earthquake and tsunami on March 11 and the nuclear crisis they created.
The Navy announced on Tuesday that the USS Ronald Reagan Carrier Strike group has ended its role in the Japan recovery effort and is repositioning in order to resume its previously scheduled operations.
The strike group, which includes the guided-missile cruisers USS Chancellorsville and USS Shiloh and destroyers USS Preble and USS Curtis Wilbur, will remain in the Pacific Command area of operations, but its next mission has not been announced.
A Navy representative said the Reagan's repositioning "is an indicator of the tremendous progress the Japanese government and the Japan Self-Defense Forces have made on the ground in dealing with this catastrophe."
The U.S. Navy now has four ships still participating in Operation Tomodachi, down from 14 ships Monday.
Department of Defense Press Secretary Geoff Morrell said that is not a sign of any reduction of America's commitment to help Japan.
"I would not, in any way, interpret the Reagan's reassignment as in any way a reflection of a diminution of focus or effort or support to the Japanese government in this hour of need," Morrell told reporters at a Pentagon briefing Tuesday.
The U.S. Air Force's efforts to help the Japanese have decreased as well. On March 23, at the height of the disaster response, the Air Force carried out at least 25 flights carrying 486 tons of food, water, fuel and other emergency supplies, according to a U.S. Air Force spokesman. On Monday, the Air Force carried out 11 flights delivering 109 tons of humanitarian aid cargo.
Morrell said Tuesday the U.S. military still has about "20,000 (people) committed to this phase of the operation, the humanitarian assistance, disaster relief."
At one time, the Defense Department said, 20,000 service members were involved. Now, according to military officials and news releases, counting the number of sailors assigned to the four Navy ships, the Marines on the ground and on board ships as well as the Air Force personnel involved, the U.S. military has about 6,700 service members involved in Operation Tomodachi.
The U.S. Army hasn't been heavily involved in the effort.
Many military personnel and ships remain in the area and could be called in to help if the situation deteriorates. The situation also is being tracked at the very highest level, according to Morrell. "The mere fact that the deputy PACOM commander, Adm. (Patrick) Walsh has been based in Japan, really for the last couple of weeks, running the joint task force there, is a sign of the commitment and the high-level commitment to this problem."
The Japanese apparently are pleased with the U.S. military's help. Japan's defense minister, Toshimi Kitazawa, in a visit to the USS Ronald Reagan on Monday, told the crew, "It is my sincere wish that those of you who will depart from the relief efforts to assume a new mission, to leave with a feeling of utmost pride for taking part in a noble operation such as Operation Tomodachi."