North Korea test launched 30 short-range rockets into the East Sea on Saturday morning, the Republic of Korea Joint Chiefs of Staff announced today.

The launch was the latest in series of short-range test launches that analysts have described as Pyongyang’s response to joint ROK-U.S. military drills.

Major Kim Nam Wook, spokesman of South Korea’s Defense Ministry, said that although the rockets tested had a range of about 60km, it was not yet clear which kind of rocket type was used. But experts say the projectiles were likely FROG (Free Rocket Over Ground) short-range rockets, similar to the Soviet-designed Luna.

On March