SEOUL – North Korea said Friday it began steps to arrest and investigate those responsible for the failed launch of its second naval destroyer after leader Kim Jong Un expressed fury over the incident that he said was caused by criminal negligence.

The 5,000-ton-class warship was damaged when a transport cradle on the ship’s stern detached early during a launch ceremony at the northeastern port of Chongjin on Wednesday, state media said. Satellite imagery on the site showed the vessel lying on its side, with most of its hull submerged and draped in blue covers.

North Korea’s official Korean Central News Agency said Friday that the severity of the damage was “not serious” and could be repaired in about 10 days. It said the hull on the starboard side was scratched and some seawater had flowed into the stern section, though it denied an earlier assessment that the bottom of the hull had been left with holes.

The extremely secretive nature of North Korea makes it almost impossible to verify the assessment. North Korea has a history of manipulating or covering up military-related setbacks, policy fiascoes and other mishaps, though it has periodically acknowledged some of such events in recent years.

Observers believe North Korea’s admission of the failed launch was likely meant to show Kim’s resolve to advance his naval capabilities and boost discipline.

The North’s Central Military Commission summoned Hong Kil Ho, manager of the Chongjin shipyard, as it begun its investigation of the failed launch, KCNA reported.

“No matter how good the state of the warship is, the fact that the accident is an unpardonable criminal act remains unchanged, and those responsible for it can never evade their responsibility for the crime,” the commission said, according to KCNA.

Kim, who was present at the failed launch, had blamed military officials, scientists and shipyard operators and ordered that the warship be repaired before a high-level ruling Workers’ Party meeting in late June.

The damaged ship is assessed as the same class as North Korea’s first destroyer, unveiled last month with great fanfare and said to be capable of carrying various weapons including nuclear missiles. Analysts say it is the North’s biggest and most advanced warship to date and was likely built with Russian assistance.

The North Korea-focused 38 North website had assessed last week that North Korea was preparing to launch the destroyer in Chongjin with a method it has rarely used. The report said the ship was being prepared to be launched sideways from the quay, while the previous destroyer launched at the western shipyard of Nampo used a floating dry dock.