Information on all the North Korean warships registered with the International Maritime Organization(IMO) has been deleted, a day after a report revealed the North's 13 submarines were listed with the organization. 

As of Friday morning, details on the North’s previously registered surface ships, such as the Nampo-class frigate FFH-3, could no longer be found through the IMO’s Global Integrated Shipping Information System.

The Voice of America reported on Tuesday that North Korea had registered 13 of its submarines with the IMO, including the Sinpo C-class Hero Kim Kun Ok submarine. 

But the newly registered submarines were taken off the IMO registry a day after the report. The number of North Korean vessels previously listed was about 180. 

When asked, the IMO told the Voice of America on Thursday that it updates its information at the request of member states.