North Korean officials have arrested four people because a navy ship they launched recently didn't work. State media said that leader Kim Jong Un stated this failure happened because of their serious carelessness.

North Korea doesn't often punish officials publicly and severely for failed weapons tests or military shows. The arrest of four officials this weekend shows how serious Kim Jong-un is about his military plans and improving discipline in the country.

A large 5,000-ton destroyer was damaged on Wednesday during a launch ceremony in Chongjin, which Kim attended. A support part at the back of the ship broke off too early. Satellite photos show the ship lying on its side and covered with blue material, with some parts of it underwater.

Kim was very angry about the incident because the warship, which is the country's second destroyer, is very important for his plans to update the navy. He quickly blamed military staff, scientists, and shipyard workers, saying it was a "criminal act" caused by extreme carelessness and not using scientific methods.

On Monday, North Korea's official news agency reported that Ri Hyong Son, a high-ranking official in the Workers' Party's weapons department, was arrested. He admitted that he was mainly responsible for the failed rocket launch.

KCNA reported on Sunday that three officials from Chongjin Shipyard were arrested because of the incident. The arrested officials were the chief engineer, the head of the hull construction workshop, and the deputy manager for administrative tasks.

Hong Kil Ho, the shipyard manager, was also asked to come in for questioning, as KCNA reported earlier.

On Thursday, North Korea's Central Military Commission told investigators that the people responsible "cannot avoid being blamed for the crime." However, it's not clear what punishment the arrested officials will receive.

When Kim first became leader, he became known for ordering many executions and removing important officials, including his powerful uncle. People believed he did this mainly to strengthen his control and get rid of anyone who might threaten his leadership. In recent years, there have been fewer reports of executions or removals in North Korea. It seems Kim has now gained complete power, similar to his father and grandfather.

Kim has reportedly given special benefits to scientists and engineers who work on weapons, as he has been trying to increase his nuclear and missile supplies. He has given them new apartments in Pyongyang. Also, after a military spy satellite launch failed last year, he sent a supportive message to his scientists about the problem, saying that "failure is always a necessary step for success," according to state media.

Experts believe Kim wants to make good progress on his five-year weapons plan, which he announced at a party meeting in early 2021. Kim has said that North Korea needs a stronger navy, nuclear missiles, and other modern weapons to deal with what he sees as growing security threats from the U.S. and its allies.

Last month, North Korea launched its first destroyer, a large 5,000-ton ship, with a lot of celebration. This ship is North Korea’s biggest and most modern warship, and state media said it can carry different weapons, including nuclear missiles. Kim Jong-un called building it "a big step forward" in making North Korea’s navy more modern.

North Korea stated that the second destroyer was not badly damaged, explaining that the right side of the ship was scratched and some water got into the back part.

North Korea said on Friday that it would take about 10 days to fix things, but many people outside the country thought the damage was probably worse than they said.