North Korea on Tuesday responded to calls made by South Korea via ship-to-ship radio links that use the global merchant marine communication network. 

The Defense Ministry said the North’s move came a day after direct communication lines linking South and North Korea were restored after about two months. 

Pyongyang responded to the South’s calls made via the western and eastern hotlines on Monday as soon as the lines were restored, but not to ones made via the ship-to-ship hotline. 

With the North responding to the latest calls, all inter-Korean military hotlines are now up and running.

The two Koreas had used the ship-to-ship hotline to avoid accidental clashes in regions near the Northern Limit Line in the Yellow Sea.