The senior commander of U.S. forces in the Pacific says the Navy probably will withdraw a group of naval vessels from waters off the coast of Burma, also known as Myanmar, within days unless the government allows the ships to offload their relief supplies for cyclone victims.

Navy Adm. Timothy Keating, chief of the U.S. Pacific Command, said Wednesday he would discuss the matter later this week with Defense Secretary Robert Gates in Singapore, where they will attend an international security conference.

Keating said the group of ships, led by the amphibious assault ship USS Essex, has other scheduled commitments in the area, including a planned port visit to Hong Kong. They happened to have been in the Gulf of Thailand participating in a naval exercise when the cyclone struck May 2-3.

"Absent a green light from Burmese officials, I don't think she will be there for weeks," Keating told a Pentagon news conference, referring to the Essex. "Days, and then we'll see."

The admiral said the Burma authorities' refusal to let the Navy provide relief aid is frustrating. He described the sailors and Marines aboard the Essex as "desperate" to provide help.

"If they can't help, they know they have other things that they joined the Navy and the Marine Corps to do, so they want to get on with that sort of thing," Keating said. "It is certainly frustrating to us at Pacific Command. Imagine how much more frustrating it is to the men and women on the ship."

The admiral said it is not too late for the Navy to contribute to the relief effort, saying, "We believe there's still a mission for us."

The Burma government has allowed a limited number of U.S. Air Force C-130s to bring in water and other relief supplies from a base in Thailand. Keating said 70 such flights have been flown thus far.

Accompanying the Essex in waters off Burma are the USS Juneau, the USS Harper's Ferry and the USS Mustin. The Essex has 23 helicopters aboard, including 19 capable of lifting cargo from ship to shore, as well as 1,500 Marines. U.S. officials have proposed using the helicopters to distribute relief aid from the Rangoon airport to outlying areas closer to the cyclone victims.

The U.S. vessels have been off the coast since shortly after the cyclone struck.

The Burma government says the cyclone killed 78,000 people and left 56,000 missing. An estimated 2.4 million people were left in desperate need of food, shelter and medical care, the United Nations says.

Keating said that when he flew to Rangoon with the first C-130 ferrying relief supplies from Thailand on May 11 he met with a high-level delegation of Burma civilian and military officials. He said they expressed appreciation for U.S. offers of more aid but said they could not make decisions at that point.

The Burma officials then spoke positively about the prospects for recovery from the cyclone, Keating said.

"As to their assessment of the need for those affected by the storm, it was a much more optimistic assessment than our embassy officials and our intelligence led us to understand," he said.

"They said people are returning to their villages, they're planting their summer rotation of crops," and they said the summer monsoons would wash away the salt water that the cyclone left in the soil and ponds. "Their estimate was not nearly as grave as ours," he said.