North Korea put four officials in prison. This was because a navy ship did not launch well. The leader, Kim Jong Un, said it was their fault because they were not careful. State news reported this.

North Korea does not often punish its officials in public when weapon tests or military shows go wrong. The arrest of four officials this weekend shows that Kim is very serious about his military plans and wants people to follow rules more strictly in the country.

On Wednesday, a big ship got damaged during a ceremony in Chongjin. Kim was there. Pictures from space show the ship on its side with blue covers, and some parts are in the water.

Kim was very angry about what happened. This warship is very important for his plan to make his navy better. He quickly said that military leaders, scientists, and shipyard workers were to blame. He called it a "criminal act" because they were very careless and did not follow scientific rules.

The Korean news agency said on Monday that police arrested Ri Hyong Son. He works for the Workers Party. Ri Hyong Son said he was very sorry because the rocket launch failed.

KCNA said on Sunday that three officials from Chongjin Shipyard were arrested because of the problem. They were the main engineer, the person in charge of building the ship's body, and a manager's assistant.

Hong Kil Ho, the shipyard manager, was also called to answer questions. KCNA said this before.

On Thursday, North Korea's Central Military Commission told investigators that the people who did this "cannot avoid being responsible for the crime." But it is not clear what will happen to the officials who were arrested.

When Kim first became leader, he was known for killing many important people, like his uncle. People thought he did this to get more power and remove anyone who might be a danger. But in recent years, there have not been many reports of these killings. Now, Kim has complete power, like his father and grandfather had.

Kim has given special help to scientists and engineers who work on weapons. He wants to make more nuclear weapons and missiles. He gave them new apartments in Pyongyang. Last year, a military spy satellite did not launch well. After this, he told his scientists that "failing is always a step to success." This is what the government news said.

Experts say Kim wants to make good progress with his plan to develop weapons. He made this plan in 2021. Kim said North Korea needs stronger ships, missiles that can carry nuclear weapons, and other modern weapons. He believes this is important because of increasing threats from the U.S. and its friends.

Last month, North Korea launched a new big warship. It is their biggest and best warship. News reports said it can carry different kinds of weapons, like nuclear missiles. Kim said building it was a big step for their navy.

North Korea said that the second ship wasn't badly damaged. They said it had some scratches on the side and a little water got into the back part.

North Korea said on Friday that it needed about 10 days to fix the problem, but many people from other countries thought the damage was probably worse.