North Korea fired short-range missiles in the West Sea at around 10:30 Friday morning.

South Korea's Joint Chiefs of Staff (JCS) said the missile tests were part of a North Korean military exercise. They said the drill was aimed at testing missile performance and improving the North's ability to carry out missile operations.

However, the JCS declined to elaborate on the number, location and exact time the missiles were fired, citing military confidentiality.

The presidential office said the missile firings seemed to be part of an ordinary North Korean military exercise.

Cheong Wa Dae added that it was monitoring the situation closely, commenting at the same time that the North would not want to strain its relations with the South.

Friday's test launches were preceded by activities that began in North Korean waters off Nampo port Tuesday.

North Korea banned all civilian ships from the waters near Nampo from Tuesday morning until noon Wednesday.

A 150-ton patrol boat was on stand-by in the area at the time. It was equipped with Styx anti-ship guided missiles, which have a range of 46 kilometers.

But no missiles were launched until Friday.