BANGKOK, Thailand — U.S. Defense Secretary Gates painted a bleak picture yesterday of the prospects for delivering international aid to suffering villagers in Burma’s devastated Irrawaddy River Delta, saying he probably was just days away from ordering an American naval group waiting off the coast to leave the area.

Speaking ahead of meetings here with Prime Minister Samak of Thailand, Mr. Gates said that most aid being delivered Burma’s main city, Yangon, was not making it to the hardest-hit areas because of inundated roads, making helicopters the only viable way to move food.

The American naval presence includes three amphibious ships, led by the Essex, which carry 22 heavy-lift helicopters, but the American aircraft have been blocked by Burma’s military government.

Calling the behavior “criminal neglect,” Mr. Gates said America has made more than 15 overtures to Burma’s leadership to use the Essex’s helicopters to deliver aid, but all had been rejected. Without a change in policy, Mr. Gates said, thousands of additional villagers will die.

“The only alternative is for the international community to force its way, and I think there was unanimity among the defense ministers … that we will not do that,” Mr. Gates said of his meeting with regional defense officials in Singapore, where he spent three days before traveling to Bangkok.

Burma’s deputy defense minister, Major General Aye Myint, told the Singapore security conference yesterday that his regime had responded quickly to the cyclone which ravaged the southern delta region and insisted that the regime welcomed international aid.

“In carrying out the relief, resettlement, and rehabilitation tasks, we will warmly welcome any assistance and aid which are provided with genuine goodwill from any country or organization, provided there are no strings attached,” General Myint said.

General Myint attended a Saturday lunch with Mr. Gates and other Asian defense ministers in Singapore, and the American defense chief said several ministers in attendance expressed their frustration with the government’s refusal to allow aid to flow more freely.

Mr. Samak also expressed deep frustration with the Burmese regime in his meetings with Mr. Gates, according to senior American officials. Mr. Samak told Mr. Gates he had visited with Burma’s leader, Senior General Than Shwe, three times in recent months and that the government’s leadership remained insular and probably would view the introduction of foreign aid workers as a military invasion.

Mr. Gates arrived in Thailand following a week of anti-government protests here that have spurred fears the recently-elected prime minister could be overthrown by a military coup similar the one that unseated the Thai government in 2006.