SEOUL, South Korea (AP) — North Korea launched a projectile off its east coast Wednesday in its second launch in two days, South Korea said.

South Koreas’ Joint Chiefs of Staff gave no further details like how far the latest projectile flew and what type of weapon was launched.

The launch happened after South Korea’s military said it had detected a launch of an unidentified projectile near North Korea’s capital region on Tuesday. It said South Korean and U.S. intelligence authorities were analyzing details of Tuesday’s launch.

Earlier this week, North Korea said leader Kim Jong Un had observed a test of an upgraded solid-fuel engine for weapons and called it a significant development boosting his country’s strategic military arsenal.

Missiles with built-in solid propellants are easier to move and conceal their launches than liquid-fuel weapons, which in general must be fueled before liftoffs and cannot last long. The latest solid-fuel engine test, the first of its kind in seven months, was in line with Kim’s stated goal of acquiring more agile, hard-to-detect missiles targeting the U.S. and its allies.