Updated

U.S. stealth fighter jets and other aircraft and troops in South Korea for joint war games will remain once the exercises are finished to act as a deterrent against North Korea, a U.S. military statement said Tuesday.

Six F-117A radar-evading airplanes and other forces have been here for the past month for training with the South's military.

The retention of the stealth fighters is likely to escalate tension on the Korean Peninsula. Washington has accused North Korea of having a secret nuclear weapons program in violation of a 1994 pact.

Pyongyang has repeatedly accused Washington of plotting to attack it. The United States says it has no such plans.

"Extending their training time in the Korean Theater of Operations affords an excellent opportunity to further enhance interoperability while also enhancing deterrence," the U.S. statement said.

A spokesman for South Korea's Unification Ministry said keeping the aircraft in the South would send a message to Pyongyang that it must not threaten its neighbors while U.S. forces are focussed in Iraq.

The statement said that in addition to an unspecified number of stealth aircraft, some F-15E fighter jets and a small Army task force would stay.

About 37,000 U.S. troops are in South Korea as a legacy of the 1950-53 Korean War.

Thousands more soldiers, navy and air force personnel have been here for the past month for war games with the South's military. The U.S. forces have also included the USS Carl Vinson.

Those exercises -- dubbed Eagle, Foal Eagle and RSOI -- are scheduled to finish on Wednesday.

The statement said more than 85 percent of the forces deployed to South Korea for the exercises would leave April 4.

The announcement came as North Korea test-fired a ground-to-ship missile, Japanese and U.S. officials said.