A joint air patrol by the Philippines with the United States was aimed at protecting territory and national interests in the South China Sea, a Philippine military official said Tuesday, after Beijing accused Manila of stirring up trouble.

Philippine fighter jets and a U.S. bomber plane flew together over the South China Sea on Monday, more than a week after their navies held joint maritime exercises in the face of simmering tensions over territorial claims in the area.

"This is to enhance both armed forces' interoperability and enhance the capabilities of our air force (in) performing its mandate of protecting our territory, sovereign rights and national interests," armed forces public affairs chief Xerxes Trinidad said.