Raymond Bonner, New York Times, Jakarta – The US ambassador here said on Thursday that the United States was not troubled by the demands by the Indonesian government that aid workers in Aceh Province register and that all foreign troops be gone by the end of March.

He described the restrictions as "reasonable" and "unremarkable." The government's intention to have foreign troops leave and take over the reconstruction after 90 days "sounds like a perfectly reasonable position to me," the ambassador, Lynn Pascoe, said at a press conference at the US Embassy.

"It's their country," he said at one point, adding that "they have every right to decide" how long American troops are needed.

Sensitive to the impression that it was relying too heavily on outside military forces and wanting to assert control over the relief operation, the Indonesian government Wednesday set a deadline of March 26 – three months after the tsunami struck – but said it hoped to phase out the foreign troops even earlier.

The timetable for the withdrawal of foreign troops was made public a day after the commander of the Indonesian military announced restrictions on the movement of foreign aid workers.

The military has fought a civil war against separatist rebels here for 30 years and has kept Aceh virtually sealed to outsiders in that period. President Susilo Bambang Yudhoyono is a former general and a strong defender of the military role in the province.

Western military officials said the Indonesian Army, the backbone of the nation's strong sense of sovereignty, was being cooperative but touchy about the foreign troops working here.

The governments of India and Thailand, nations also hit by the tsunami, said they could cope on their own. But out of a total death toll exceeding 150,000, Indonesia accounts for more than 100,000, and it accepted help from foreign troops when it became clear that its own military could not deal with the devastation.

A number of countries have sent or are sending troops to help. The American military has taken a major role, flying daily helicopter runs to ferry food to isolated villages devastated by the wave and bringing wounded people to hospitals Banda Aceh, the capital of Aceh.

This is a highly nationalistic country, and the Bush Administration is clearly concerned about the reactions of many Indonesians to the presence of the American soldiers, which has begun to show up in the restrictions imposed by the government. American diplomats, even at the senior level are not supposed to speak officially without approval from Washington, and in the past several years, there have been fewer than a handful of official remarks by American diplomats here.

On Thursday, Pascoe, a career diplomat who took up his post here three months ago, not only spoke officially but also called a news conference, heavily attended by Indonesian journalists. Pascoe stressed repeatedly the theme that this was an Indonesian operation.

"I want to be very clear about that," he said. "This is a cooperative effort. We are here at the request of the Indonesian government. We are here as long as there is a task that needs to be done, that they want us to work on. And we have every intention to leave immediately when that point is reached."

Nor, he said, did the United States military have any problems with allowing an Indonesian soldier on American helicopters. Indeed, this has been happening since the first days of the relief operation, he said. Pascoe added, "We don't do anything up there that is not totally in support of the government of Indonesia."

The Indonesian government has said that its restrictions on aid workers in Aceh are necessary for the protection of the aid workers. Aceh has been torn by a civil war for nearly 30 years, between the government and separatist rebels of the Free Aceh Movement, better known here by its initials, GAM. In recent days, rebel leaders have declared that they have no intention to harm any foreign relief workers and that they were extending their cease-fire which they announced soon after the tsunami.

Many Indonesians, and foreign diplomats, do not accept the government's reason for the restrictions at face value. It is more likely they say that the military wants to reassert control over the province, they say. Prior to the tsunami, the area was under martial law, and foreign journalists were not allowed in.

Pascoe defended the government's requirement, announced this week, that all aid workers register. "They're saying register your people," he said. "I find that totally unremarkable. Every government has the right to check on foreigners in their country."

Pascoe also bristled when he was question, again, about the motivation behind the US relief efforts. Was they to improve America's image with Muslims, in light of the Iraq war, he was asked, and to open up Aceh, which is rich in natural resources, to American companies?

Those notions are "as wacky as they can be, and I would just say flatly they are foolish." What the United States was doing was perfectly clear – save lives and alleviate suffering. "We're trying to make this a better world."

[Jane Perlez contributed reporting for this article from Banda Aceh.]