South Korea's Joint Chiefs of Staff(JCS) said that North Korea fired an unspecified ballistic missile toward the East Sea on Thursday. 

The test followed joint drills by South Korea and the United States and a return of a U.S. nuclear-powered aircraft carrier to the East Sea.

The South Korean military is conducting a detailed analysis of the launch, including the range, altitude and speed.

The latest launch comes just two days after the North fired an intermediate-range ballistic missile over Japan from the area of Mupyong-ri in Chagang Province. 

Thursday's missile launch was the sixth in 12 days.