BANGKOK  In the strongest remarks yet by a high-ranking American official, Defense Secretary Robert M. Gates said on Sunday that Myanmar was guilty of “criminal neglect” for blocking large-scale international aid to cyclone victims, and that more Burmese civilians would perish unless the military regime reversed its policy.

But despite the rising anger and frustration with Myanmar’s military leaders, Mr. Gates said that defense ministers meeting in Singapore over the weekend had unanimously opposed any plan to violate Burmese sovereignty and forcibly provide relief supplies.

As a result, he said, it was probably a matter of days before the Pentagon withdrew four Navy ships carrying supplies that have been “steaming in circles” for days in the waters off Myanmar’s coast, waiting in vain for permission to ferry their cargo to areas hit by the storm.

“It’s becoming pretty clear that the regime there is not going to let us help,” Mr. Gates told reporters in Singapore before he headed to Bangkok on the third leg of a weeklong trip to Asia. “I’d say that unless the regime changes its approach, changes its policy, more people will die.”