MANILA, Philippines >> More than 5,000 U.S. and Filipino troops began two weeks of military exercises Monday to prepare to jointly deal with any potential crisis in the Philippines, which is prone to natural disasters and has been locked in a dangerous territorial standoff with China.

U.S. and Philippine military officials said at an opening ceremony that 3,000 Filipino soldiers and 2,500 American military personnel would take part in the annual “Balikatan,” or shoulder to shoulder, exercises, the largest of several military drills the allies stage each year.

American and Philippine officials said the maneuvers would focus on maritime security and disaster response, but avoided linking the war games with their concern over China, which they have criticized for its increasingly assertive behavior in disputed South China Sea territories.

The Philippines, the oldest of Washington’s five defense treaty allies in Asia, has turned to the U.S. to modernize its ill-equipped military amid the increasingly tense territorial rifts with China.

Dozens of left-wing activists protested outside the main military camp in the Philippine capital, Manila, where the opening ceremony was held. They said the drills and a recently signed agreement that allows a larger U.S. military presence in the country would violate the Philippine Constitution, which prohibits foreign troops except when their presence is covered by a treaty.

Australia deployed 65 army soldiers and air force personnel to participate in live-fire maneuvers and charity activities. It also deployed a P3 Orion aircraft for a surveillance exercise with U.S. and Philippine military counterparts, Royal Australian Air Force Wing Commander Nicholas Pratt said.

Australia has signed an agreement with the Philippines that allows its forces to hold military exercises with Filipino troops in the country, the only other such pact Manila has signed aside from the United States.

Philippine Foreign Secretary Albert del Rosario said the exercises would strengthen the countries’ capability to deal with increasing tensions “due to excessive and expansive maritime and territorial claims” and “aggressive patterns of behavior” that threaten regional peace and stability.

The exercises will be held in military camps in the northern and western Philippines, including in Zambales and Palawan provinces on the edge of the South China Sea. The maneuvers will include maritime surveillance exercises, live-fire drills, training on handling bombs and “mass casualty response,” a Philippine military statement said.

China, the Philippines, Brunei, Malaysia, Taiwan and Vietnam have overlapping claims in potentially oil- and gas-rich areas in the busy South China Sea, with Beijing laying claim to virtually the entire body of water.

The territorial spats between Beijing and Manila have worsened after Chinese government ships effectively gained control of the disputed Scarborough Shoal in 2012 then blockaded the Second Thomas Shoal, where Philippine marines have been based on a grounded navy ship since 1999.

Chinese coast guard ships have twice attempted to block Philippine ships bringing in food and fresh batches of marines to Second Thomas Shoal, increasing tensions. A Philippine military plane dropped food supplies and letters from Filipino supporters to the marines marooned at the Second Thomas Shoal over the weekend.