MANILA – Pentagon chief Chuck Hagel will discuss expanding the US military's presence in the Philippines in a visit to the country Friday as Manila looks to defend its territorial claims in disputed waters.

Hagel flew into Manila on Thursday amid fresh strains between the Philippines and China over disputes in the East Sea, with President Benigno Aquino calling off a visit to Beijing next week at China's request.

The Philippines has accused Beijing of an arms buildup and coercive moves in the strategic East Sea, which is believed to hold unexploited oil and gas deposits.

China, after asking President Aquino to call off his visit, cited "difficulties" in relations with the Philippines.

Manila has sought out military assistance from Washington, including ships and radar, to better monitor coastal waters and fend off what it alleges is a Chinese bid to gradually seize control of disputed islets.

During his visit, Hagel is expected to discuss a proposed agreement to permit more American troops, ships and aircraft to pass through the Philippines on temporary deployments, officials said.

Hagel will hold talks with President Aquino before meeting his counterpart, Voltaire Gazmin, and Foreign Affairs Secretary Albert del Rosario, officials said.

Hagel flew to Manila on Thursday at the end of a week-long tour of Southeast Asia in which an escalating US confrontation with Syria has repeatedly intruded on his trip.

The defence secretary's discussions in Malaysia, Indonesia and Brunei over the past week have focused on bolstering US military ties in a region facing growing tensions over maritime disputes.

At a gathering this week in Brunei of defence ministers from Southeast Asia and other countries, Hagel warned his counterparts that attempts to assert territorial claims "increase the risk of confrontation, undermine regional stability, and dim the prospects for diplomacy".

The Philippines once hosted tens of thousands of US soldiers at two bases near Manila, but they were forced to leave in 1992 after the Philippine Senate voted to end their lease contracts amid strong anti-American sentiment.

A new accord in 1999 allowed US troops to return to the Philippines for joint military exercises every year.