Defense Secretary Voltaire Gazmin said the increase is not aimed at China, and is only temporary, Philippine Inquirer.net reported.
"[China] shouldn't be agitated because we have a treaty with the Americans, and that includes helping us to be capable of protecting our territories and addressing disaster operations," Gazmin said.
Several hundred U.S. troops have been deployed to the southern island of Mindanao, where they are training and advising local forces on how to fight terrorism.
China has expressed concern about the U.S.' growing interest in the Far East after spending many years concentrating on the Middle East.
"There are some countries which are strengthening their Asia Pacific military alliances, expanding their military presence in the region and frequently make the situation there tenser," the Chinese defense ministry said in a report.
In a visit to the Philippines last week, U.S. Defense Secretary Chuck Hagel said the United States would not establish bases in the Philippines.