Philippine Ambassador Manuel Lopez says his nation should bolster maritime cooperation with Japan and the United States as it seeks to deter China's growing assertiveness at sea.

In an interview Friday in Tokyo, Lopez said the Philippines is "not a military power" and is "very vulnerable to more incursions by China," adding Manila needs the help of countries such as the United States and Japan to help resolve ongoing maritime problems.

"I'm rather alarmed at recent developments, especially after seeing photographs of some structures being built," he said, referring to images of apparent land reclamation work by China under way at the contested Johnson Reef, a shoal it controls.