North Korea has arrested a fourth official over the failed launch of a new warship that has enraged the country's leader, Kim Jong Un. Ri Hyong-son, deputy director of the ruling Workers' Party's Munitions Industry Department,

Satellite images and videos show how launching a 5,000-ton warship into the water sideways can cause it to capsize if done incorrectly.

North Korea said on Friday it had righted a capsized destroyer and moored it at a pier in the northeastern port of Chongjin as it continues to repair the new warship that Kim Jong Un has described as a significant asset for his nuclear-armed military.