JAKARTA, Indonesia —From Manado on the northern tip of this sprawling Indonesian archipelago to Banda Aceh on its western edge, the commanding officer of U.S. forces in the Pacific and Asia has been out inspecting a front line in the war on terror.

"I wanted to see for myself," Adm. William J. Fallon said after a long flight from this capital to the far end of the island of Sulawesi (formerly Celebes) next to the Celebes Sea. The islands surrounding that sea have become highways, or what some Americans call "rat lines," for terrorists moving men and materiel to and from Indonesia, Malaysia and the Philippines.

Similarly, he flew to the island of Sumatra that stretches alongside the vital and vulnerable Strait of Malacca to look at Indonesian defenses. Through that channel and the South China Sea pass more ships every year than through the Panama and Suez canals combined, making those sea lanes crucial to the economies of East and Southeast Asia and, indirectly, to the rest of the industrialized world.

Piracy has been rampant in those waters for more than five years, although American and Indonesian officials say it has dropped recently. U.S. and Southeast Asian intelligence services have been watching for possible links between the pirates, who are criminals, and terrorists, such as Jemaah Islamiya, who may seek to close the Malacca Strait to cause political and economic disruption.

Terrorists struck the island of Bali in 2002, Jakarta in 2003 and 2004, and Bali again last October. Moreover, Indonesia is the world's largest nation in which the Islamic religion dominates. U.S. and Indonesian officials worry that it may have become a source of terrorist recruits.

Fallon began his journey in Jakarta, where he conferred with President Susilo Bambang Yudhoyono and senior defense officials. "I came to solidify our relationship and to see where we go from here," he said. He referred to military relations recently revived when the U.S. lifted restrictions imposed several years ago to protest human rights violations by Indonesian forces.

In Manado, Fallon conferred with local political, military and police leaders, and was piped aboard an Indonesian frigate just before it went back on patrol in the Celebes Sea. "I was surprised," he said later, "at how much security they have up here. The police chief told me that if anyone comes ashore in that area, the police will know about it within 24 hours."

Even so, Fallon underscored his concerns about terrorists in this region just by his presence. The Celebes Sea is remote from the capitals of Jakarta, Kuala Lumpur and Manila, and therefore seems to be out of sight and out of mind of leaders there. Fallon's subtle message was that they should pay more attention to the threat of terror from the Celebes Sea.

In Medan, on Sumatra, Fallon heard Indonesia naval and police officers say they had only 32 small boats and three larger boats to chase pirates. They told the admiral that the United States could help them best with training and equipment. They were adamant, however, that they should do the patrolling themselves.

"Do not send U.S. ships to patrol here," said an Indonesian officer.

"Indonesia and Singapore," which is just across the strait, "want to solve this issue ourselves," said another. As with all Southeast Asian nations, the anti-colonial legacy is still strong, and they are sensitive to actions they perceive to be an intrusion on their sovereignty.

Fallon readily agreed, pointing out that the U.S. Navy had extensive commitments elsewhere and that he wanted only to help the Indonesians acquire the capabilities they need. "It's your neighborhood," he said, "and you should do it yourselves."

Critical to defending the strait against pirates and terrorists will be the success of a peace agreement between the Indonesian government and separatists in the Free Aceh Movement, known as GAM, which fought each other for more than a decade. A memorandum of understanding between them was signed last August.

In Banda Aceh, which was devastated by the tsunami of December 2004, Fallon met with local officials of the Indonesian government, leaders of the GAM, and the international mission that is monitoring the execution of the peace agreement. It includes provisions for disarming the GAM and reducing the number of Indonesian troops and police in this region.

The admiral encouraged them to continue working together, asserting that "Little is ever settled by force of arms."

Richard Halloran is a Honolulu-based journalist and former New York Times correspondent in Asia.