Construction of the projects in three of five Philippine sites outlined under the Enhanced Defense Cooperation Agreement (EDCA) will start next year, the Department of Defense said in a statement.

"The department is committed to accelerate the implementation of the EDCA by concluding infrastructure enhancement and repair projects, developing new infrastructure projects at existing EDCA locations," it said.

The Philippines has long been a staunch U.S. ally and the EDCA is widely seen as important for both sides, worried by China's increasingly assertive pursuit of its territorial claims in the South China Sea.

The two countries have a 70-year-old Mutual Defense Treaty and take part in dozens of joint training exercises each year, ranging from live fire and amphibious assaults to humanitarian missions and counter-terrorism drills.

EDCA allows the United States to maintain a military presence in its former colony through rotation of ships and aircraft for humanitarian and maritime security operations.

On Monday, Philippine military chief Bartolome Bacarro said the United States had proposed including five more military bases in the EDCA, but that would be subject to approval by the defence and foreign ministries.

(Reporting by Karen Lema; Editing by Martin Petty)