Admiral Timothy Keating says after 70 U.S. military relief flights from Thailand into Rangoon, carrying some 370 metric tons of supplies, he can not say for sure whether the aid is being distributed to the area devastated by a cyclone early this month.

"It remains a challenge, still," he said. "The goods end up in Rangoon. Subsequent distribution is handled by non-governmental organizations to a limited degree, and to a larger degree by the government of Burma. Do we know where they're going? I do not necessarily know where those relief supplies are going."

US Not Sure Aid Reaching Burmese Victims, May Remove Ships

Admiral Keating told reporters he gets reports from non-governmental organizations that have relief workers in Burma, but the information is not comprehensive.

US Not Sure Aid Reaching Burmese Victims, May Remove Ships

"We have reasonable confidence, but not 100 percent confidence that the folks who need it, they're receiving it," he said. "The stuff we're sending is of little high value. Everyone will recognize how desperately the material we're providing is needed down range. So there is a certain amount of faith that it is getting down range. And the NGOs who are moving around report some evidence of its distribution. But it's complicated."

US Not Sure Aid Reaching Burmese Victims, May Remove Ships

United Nations officials say aid agencies have reached about 40 percent of the storm's victims.

So far, Burmese leaders have only allowed the U.S. military flights from Thailand. They have refused to allow the USS Essex and other U.S. navy ships off their coast to deliver larger quantities of relief and medical supplies. The ships have been on station in international waters for two weeks, and Admiral Keating says he can not keep them waiting there much longer, unless Burma allows them to get involved in the relief effort.

"Absent a green light from Burmese officials, I don't think she will be there for weeks," he said. "A couple of days and then we'll see."

The admiral expressed frustration that so much badly needed aid is sitting in Thailand and off the Burmese coast, and he can not get permission to deliver it.

"All it would take is, "Yes," and there would be significant material going ashore within an hour, I'd say," said Admiral Keating.

Admiral Keating said U.S. officials in Thailand believe Burmese leaders may be easing their objections to larger scale aid deliveries, but he is not sure whether there will actually be a change in policy.

The admiral also said he would "look favorably" on a plan for Burmese boats to take the relief supplies from the U.S. ships and bring them ashore. Britain's Department for International Development says Burma has agreed to such an approach, but Admiral Keating says he has not heard about it.