South Korea's military says North Korea has fired four short-range projectiles into the sea.

Seoul's Joint Chiefs of Staff said in a statement that the projectiles with a range of 87 miles were fired Friday into waters off North Korea's west coast.

North Korea regularly test-fires missiles, rockets and artillery. It has conducted a series of weapons tests since South Korean and U.S. troops began annual military drills last month.

North Korea has denounced the drills as a rehearsal for an invasion.

South Korea and the U.S. say the drills are defensive in nature. The training is set to end later this month.