North Korea said it was cutting off all communication channels with South Korea on Tuesday, a move experts say could signal Pyongyang has grown frustrated that Seoul has failed to revive lucrative inter-Korean economic projects and persuade the US to ease sanctions.

The North-s Korean Central News Agency said all cross-border communication lines would be cut off at noon in the "the first step of the determination to completely shut down all contact means with South Korea and get rid of unnecessary things."