North Korea fired two short-range ballistic missiles (SRBMs) toward the East Sea (Sea of Japan) in a rare early morning launch on Wednesday, hours after South Korea announced a U.S. nuclear missile submarine had arrived in the port city of Busan.

South Korea’s Joint Chiefs of Staff (JCS) said the North launched the two SRBMs from the Sunan area north of the capital. North Korea frequently launches missiles from the Pyongyang International Airport in Sunan.