MANILA, Philippines (AP) — A new defense pact that will allow thousands of U.S. troops to be temporarily based in Philippines for the first time in more than 20 years signals closer cooperation in the allies’ hot-and-cold relationship that has been shaped over the decades by war, terrorism and now, jitters over China’s rise.

The 10-year agreement, signed Monday as President Barack Obama arrived in Manila, is considered the centerpiece of his four-nation Asian trip, which he used to reassure allies like Japan and the Philippines of American military backing as they wrangle with China in increasingly tense territorial disputes.