SEOUL, South Korea — Kim Jong-un, North Korea’s leader, has inspected a newly built submarine, the state news media reported on Tuesday, a provocative move as the United States struggles to resume dialogue on ending the country’s nuclear and missile threats.

The North’s official Korean Central News Agency said the country planned to deploy the new submarine soon in waters off its east coast.

The report included three photographs of Mr. Kim visiting a shipyard where the submarine was built. The photos showed part of the submarine, but the article revealed no technical details on the submarine. It also did not specify when Mr. Kim made the visit.

Along with its intercontinental ballistic missiles, North Korea’s submarine and submarine-launched ballistic missile programs pose one of the biggest military threats to the United States and its regional allies because they can extend the range of the North’s nuclear missiles. Submarine-launched missiles are also harder to detect in advance.