Story highlights US official describes projectiles as intermediate-range missiles

Japan, US blast North Korean action

(CNN) A North Korean military unit tasked with striking US bases in Japan was involved in Monday's launch of four ballistic missiles, according to state media KCNA.

The missiles, three of which landed within 200 miles of Japan's coastline in its exclusive economic zone, were fired as part of a drill by North Korea's Hwasong artillery units, KCNA said Tuesday.

The report said the units were part of "the KPA Strategic Force tasked to strike the bases of the US imperialist aggressor forces in Japan in contingency."

Photos: North Korea launches four missiles into sea off the coast of Japan The four missiles were launched from near Tongchang Ri in North Korea's northwest, South Korea's military said. Hide Caption 1 of 8 Photos: North Korea launches four missiles into sea off the coast of Japan North Korean leader Kim Jong Un (C) supervised the launch of four ballistic missiles on Monday March 6, according to the country's state media. Hide Caption 2 of 8 Photos: North Korea launches four missiles into sea off the coast of Japan North Korean leader Kim Jong Un appears to watch the launch of the four ballistic missiles on March 6, in a photo from state media. Hide Caption 3 of 8 Photos: North Korea launches four missiles into sea off the coast of Japan Three of the four missiles landed inside Japan's exclusive economic zone, less than 200 miles from its coastline, according to Japan's Prime Minister Shinzo Abe. Hide Caption 4 of 8 Photos: North Korea launches four missiles into sea off the coast of Japan According to North Korean state media, the units which fired the missiles are tasked to strike US bases in Japan, in the event of a war. Hide Caption 5 of 8 Photos: North Korea launches four missiles into sea off the coast of Japan North Korean leader Kim Jong Un, pictured here on March 6, was said to be pleased with the launch, according to state media. Hide Caption 6 of 8 Photos: North Korea launches four missiles into sea off the coast of Japan South Korea, Japan, China and the United States all issued statements opposing the launch on March 6. Japan's Prime Minister Abe called it an "extremely dangerous action." Hide Caption 7 of 8 Photos: North Korea launches four missiles into sea off the coast of Japan North Korean leader Kim Jong Un (C) stands with troops on March 6, according to state media. Hide Caption 8 of 8

North Korean leader Kim Jong Un supervised the country's ballistic missile launches and was said to be pleased with the unit's performance, according to KCNA.

There are currently about 54,000 US troops stationed in at least seven bases scattered across Japan, including Misawa Air Base in the far north to Okinawa on the country's southernmost islands.