North Korea has built a new submarine believed to be capable of carrying at least three ballistic missiles and is gauging the right time to unveil it, a local news outlet said Sunday, citing anonymous Seoul officials familiar with the matter.

“South Korea and the US believe North Koreans have finished building one that they revealed in 2019,” Yonhap News Agency quoted the officials as saying. The North’s state media released a photograph at the time, in which leader Kim Jong-un was shown inspecting the submarine.

“North Korea could test-fire a ballistic missile on that submarine after the rollout ceremony,” the officials said. The submarine is believed to be a modified Soviet-era Romeo class model built at the Sinpo South Shipyard along the east coast. The port city is home to the North’s fleet of submarines.

North Korea is also building a larger submarine that could carry advanced ballistic missiles, the report said, referring to the Pukguksong-4 and -5 missiles it revealed in 2020 and 2021 during a military parade and a key party meeting, respectively. The Pukguksong-3 was tested in October 2019.

On Thursday, 38 North said, based on satellite images it reviewed, that North Korea could be preparing to either roll out a new ballistic missile submarine or conduct a submarine-launched ballistic missile test. It could also be just general maintenance, according to the website that monitors the isolated country.

North Korea, which tested its first SLBM in 2015 when Kim Jong-un oversaw the launch, last conducted an SLBM test with the Pukguksong-3 in 2019, when it pushed ahead with the launch hours after it announced it would resume nuclear talks with the US.

Kim Jong-un is seen as trying to step up pressure on the US to unveil more favorable measures toward Pyongyang as Washington is in the final stages of fine-tuning details of a new North Korea policy.

The US, which has said it is looking at both sanctions and dialogue to engage the isolated regime, has slammed North Korea’s rights abuses in a shift to a hard-line approach to the North. Pyongyang has responded with missile tests, having brushed off Washington’s behind-the-scenes outreach since February.

By Choi Si-young (siyoungchoi@heraldcorp.com)