SEOUL, South Korea -- Japan says North Korea has launched a suspected missile toward the sea.

Japan’s coast guard said it confirmed that what appeared to be a North Korean missile was fired Sunday morning.

Further launch details were not immediately available, it said.

South Korea’s Yonhap news agency cited the South’s military as saying that North Korea had fired a ballistic missile toward its eastern waters.

Calls to the South’s Joint Chiefs of Staff were not immediately answered on Sunday.

The launch, if confirmed, would be the North’s fourth round of weapons tests since the U.S. and South Korean militaries began joint military drills last week.

The North views the drills as an invasion rehearsal.