Ri Yong Ho, a senior military official from North Korea, said during a speech to mark the 80th anniversary of the military that Pyongyang wouldn't tolerate any violation of its territory.
"Our military and people will cut off the windpipes" of those who do so, South Korea's Yonhap news agency quoted him as saying.
U.S. and Philippine war games were conducted as part of an annual exercise in the South China Sea. Similar drills were conducted by U.S. and South Korean forces in early April.
Ri said the North Korean military was on high alert.
South Korea, meanwhile, announced last week it had deployed missiles with a range of 625 miles.
South Korea President Lee Myung-bak was scorned by North Korea for complaining revenue spent on lavish celebrations marking the 100th birthday of North Korean founder Kim Il Sung could have helped feed North Koreans.
A North Korea rocket meant to deploy an Earth observation satellite into orbit failed minutes after its April 13 launch. Pyongyang is suspected of preparing for an imminent test of a nuclear device.
The North Korean government had said it would place a moratorium on missile and nuclear tests in exchange for substantial food assistance from the United States. The deal collapsed after the April 13 launch, however.