Missile launch: Was North Korea practicing to strike US bases in Japan?

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."

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.

The military bases in Japan cost the US government about $5.5 billion in 2016.