North Korean leader Kim Jong Un has vowed to dole out stern punishments after a rare admission of a “serious accident” involving a new 5,000-ton destroyer, state-run media reported Thursday.

The accident, which took place as Kim attended a launching ceremony at the Chongjin Shipyard on the country’s eastern coast, saw “sections of the warship's bottom crushed,” destroying the vessel's balance, according to the official Korean Central News Agency.

The South Korean military said the warship — which is believed to be similarly equipped to the 5,000-ton Choe Hyon destroyer that the North unveiled last month — was lying in the water on its side, the Yonhap news agency reported, citing an unidentified defense official. The North had apparently attempted a side launch, something it had never tried before.