MANILA, Philippines — The Philippines and the U.S. will sign an agreement tomorrow that will boost the American troop presence in the Southeast Asian nation, as it seeks to counter China’s assertiveness over territorial disputes.

Philippine Defense Secretary Voltaire Gazmin and U.S. Ambassador to the Philippines Philip Goldberg will sign the accord for “enhanced defense cooperation” a few hours before U.S. President Barack Obama starts a two-day state visit, Primitivo Berunia, a media relations officer in the Philippine defense department, said by phone.

President Benigno Aquino is strengthening military alliances with countries like the U.S., which is treaty-bound to defend the Philippines in case of attack, as China pushes its claims in the South China Sea. The agreement is also aimed at bolstering Obama’s economic and security rebalancing to the Asia-Pacific region.

A draft deal reached earlier this month respects Philippine sovereignty and prevents the permanent stationing of U.S. troops and the U.S. having military bases or weapons of mass destruction in the country, the Philippine defense and foreign affairs departments said in a statement on April 11. U.S. access to and use of Philippine military facilities will be at the invitation of the Philippines and with full adherence to its laws, the defense department said.

Chinese Coast Guard ships tried to drive away a Philippine supply ship in Ayungin shoal on March 29, before the Philippines filed evidence to a United Nations arbitration body handling its complaint against China. China, which spends 47 times more on defense than the Philippines, has rejected arbitration to resolve the disputes over parts of the South China Sea, insisting on bilateral talks.

China has accused the Philippines of illegally occupying Ayungin Shoal, where Filipino troops have been stationed after a naval ship ran aground in 1999. The Philippines and Vietnam reject China’s map of the sea, first published in the 1940s, as a basis for joint exploration of oil and gas.

The Association of Southeast Asian Nations is seeking a code of conduct for the South China Sea. The talks have made little progress since China agreed last July to start discussions, and China introduced fishing rules in January requiring foreign vessels to seek permission before entering waters off its southern coast.

Aquino and Obama will discuss security issues and potential Philippine entry to the 12-nation Trans-Pacific Partnership trade pact, Communications Secretary Sonny Coloma said on April 23.

Protests are planned in Manila throughout Obama’s visit, Renato Reyes, secretary-general of a militant group known as Bayan, said by phone today. The group will protest the U.S. pivot to Asia and the TPP, he said.