Jane Perlez, Singapore – Paul D. Wolfowitz, the United States deputy secretary of defense, warned the Indonesian Army today that its war against separatist rebels in the northern province of Aceh could not be won militarily.

In a second rebuke to Indonesia, Mr. Wolfowitz, who was the American ambassador to the country in the late 1980's, said the Indonesian government had to be more forthcoming with the United States over who was responsible for the killing of two Americans during an armed attack in the eastern province of Irian Jaya last year.

The Indonesian military began a large-scale offensive against separatist guerrillas in Aceh nearly two weeks ago, after peace talks collapsed. The government said it would no longer tolerate the demands for independence by the rebels, who have resisted successive army campaigns against them for nearly 30 years.

Mr. Wolfowitz, who is considered one of the staunchest supporters of the Indonesian military in the Bush administration, offered the criticisms after meeting here with the Indonesian defense secretary, Matori Abdul Djalil. The two men were attending a conference on defense issues in Asia organized by the London-based International Institute for Strategic Studies. Mr. Matori stood beside Mr. Wolfowitz as he delivered the admonishments at a news conference.

The Bush administration has been trying to find ways to restore financial aid to the Indonesian military, which lost American aid in the 1990's because of human rights abuses by the army in East Timor. In the past year, the Pentagon has offered the Indonesian army training in counterterrorism and won congressional approval to restart a prestigious, though limited, program of training in the United States for Indonesian officers.

But Mr. Wolfowitz suggested today that these new measures might be in jeopardy, or at the very least would go no further, if the Indonesian military and its civilian overseers did not do more to meet the administration's expectations.

A number of civilians have been killed already in the current campaign, which the government says will last for six months. The government has warned foreign aid organizations to leave the province.

In one incident last week near the Bireuen regency, south of the capital of Bande Aceh, the military said that 10 people, including a 13-year-old, were killed in a firefight. But eyewitnesses said some of these people were summarily executed, an account that Western military experts in Jakarta said appeared to be correct.

Mr. Wolfowitz said the United States understood the concern that Indonesia had for preserving its territorial integrity. "At the same time we believe very strongly the solution has to be a political one," he said. He urged the Indonesians to accept the offers of nongovernmental organizations to act as monitors in Aceh. "I told the minister that it would be helpful if actions of the armed forces are transparent," he said.

The National Commission on Human Rights said this week that it would press ahead with sending its members to Aceh to observe events there, despite reservations expressed by the government about their plans.

Mr. Wolfowitz took a particularly strong stand on the lack of progress on the investigation into the deaths last August of two American teachers whose vehicles came under fire as they returned from a picnic in Irian Jaya. They were employees of the New Orleans-based mining company Freeport-McMoran Copper and Gold.

A report by the Indonesian police in Irian Jaya, headed at the time by the respected Made Mangku Pastika, concluded there was a "strong possibility" that the Indonesian military was behind the killings. Some American officials agreed with Mr. Pastika's findings at the time.

"The issue of the Freeport killings is a very important issue," Mr. Wolfowitz said. "We have made it clear at the highest level we need satisfactory cooperation from Indonesia or it will affect our whole relationship."

An American official familiar with the proceedings of Mr. Wolfowitz's meeting with the defense minister said the deputy secretary had made it clear that the Bush administration was demanding the civilian and military branches of the Indonesian government to be more forthcoming on the deaths of the Americans.

A team from the Federal Bureau of Investigation has visited Irian Jaya on several occasions but has been frustrated in its efforts to conclude an investigation by lack of cooperation by the Indonesians, a senior American official said.

The deaths of the Americans, Rick Spier of Colorado, and Ted Burgon of Oregon, has taken on a new urgency in the last several weeks as the widow of Mr. Spier, Patsy Spier, has traveled to Washington and lobbied Congress and the Bush administration to make a definitive investigation. Mrs. Spier met with Mr. Wolfowitz earlier this month. She made an impression with her arguments, Pentagon officials said. Members of the Senate Foreign Relations Committee also met with her.

Last week, the committee voted unanimously to urge the Bush administration not to go ahead with spending $400,000 that was approved last year for training Indonesian officers in the United States. The approval was interpreted by the Indonesian government as a symbolic victory of a restoration of ties, even though the funding was very low.

The committee said the administration should certify that the Indonesian military was cooperating with the F.B.I. on the Irian Jaya killings before starting the training known as the International Military Education and Training program.