MANILA — Amid concerns in the Philippines about the future of its military alliance with the United States, the aircraft carrier Ronald Reagan moored off Manila this week to show support for an ally locked in a territorial dispute with China.

The visit comes shortly after President Rodrigo Duterte told the Philippine Congress that he couldn’t do anything to ward off China’s claims in the South China Sea and would rather negotiate with Beijing than risk a potentially disastrous war.

The aircraft carrier was meant to send a different message: that the Philippines could rely on the naval might of the United States, its military ally for decades. To drive home the point, local journalists were invited to tour the Ronald Reagan on Wednesday.

The carrier “is very capable and ready to respond to a wide range of operations, whether they be crisis or whether they be a humanitarian disaster response,” said Rear Admiral Karl Thomas, commander of Task Force 70, which includes the Ronald Reagan.