Pyongyang launched three missiles Tuesday morning in the latest in a set of controversial ballistic tests, according to South Korea’s military, which claimed the projectiles had a range of up to 600 kilometers (360 miles).

The three missiles were launched from the North’s east coast into the sea at between 5:45am and 6:20am local time.

Previously, South Korea’s Ministry of Unification warned that the North was “fully prepared” and could conduct a fifth nuclear test.

“North Korea seems to be fully prepared to carry out a nuclear test at any time (when the order is given by its leader Kim Jong-un). South Korea is closely monitoring every move at the North’s test site in close cooperation with the United States,” unification ministry spokesman Jeong Joon-hee said at a regular press briefing.

Over the weekend, American intelligence reports and South Korean data revealed an increase in activity at the North’s nuclear test site in Punggye-ri, Yonhap news reported.