The Philippines and the United States have signed an agreement to allow a bigger US military presence on Filipino territory, hours ahead of a visit to Manila by US President Barack Obama.
Philippine Defence Minister Voltaire Gazmin and US ambassador Philip Goldberg on Monday signed the 10-year pact, which is seen as another element of Obama's effort to focus US military and economic attention more heavily on Asia.
Obama said the deal would see more US troops rotate through the Philippines for joint military training exercises, but emphasised there would be no return of permanent American bases.
"Greater cooperation between American and Filipino forces would enhance our ability to train, exercise, and operate with each other and respond even faster to a range of challenges," Obama said in a written response to questions by local television network ABS-CBN ahead of his visit.
The deal announced on Monday is only a framework agreement, with the details - such as how many US troops will rotate through the Philippines and when - to be negotiated and announced later.
Obama was due to arrive in the Philippines from Malaysia on Monday afternoon for a two-day visit, the final leg of an Asian trip that also took him to Japan and South Korea.
The United States and the Philippines are already long-time allies bound by a mutual defence pact, and engage in regular war games that see thousands of US troops and state-of-the-art American military hardware brought to the Philippines.
The Philippines had been eager for an agreement to expand the arrangement to boost its weak military capabilities and emphasise its close ties to the United States, at a time of deep tensions with China over competing claims to parts of the South China Sea.
China claims most of the South China Sea, even waters close to the Philippines and other countries in the region.
As tensions over the South China Sea have heated up, the United States has sought to strike a balanced strategy by seeking to reassure its allies in Asia while emphasising to China it takes no sides on the dispute.
In his comments to ABS-CBN, Obama again emphasised the United States remained deeply committed to supporting the Philippines, a former US colony, referring to the two nations' 1951 mutual defence treaty.
"We've pledged ourselves to our common defence for more than six decades. Our treaty obligations are iron-clad," Obama said.
Nevertheless, the mutual defence pact does not specifically state that the United States must come to the Philippines' defence over remote islets and reefs in the South China Sea.
Obama called on China not to use intimidatory tactics to assert its claims.
"The United States and China need to support efforts among claimants to peacefully manage and resolve maritime and territorial issue through dialogue, not intimidation, including in the South China Sea," the US leader said.