The Joint Chiefs of Staff says it has detected no particular movement by North Korea since the South Korean patrol boat Cheonan sank Friday evening.

A surveillance network that confirms the movements of aircraft or ships in the North in real time picked up no singular signs. The Joint Chiefs of Staff added that it did not raise the surveillance level for the communist state.

North Korean media have also said nothing unusual since the sinking. The North had issued statements six hours after three inter-Korean naval clashes in the Yellow Sea, but has said nothing on the Cheonan.

The Unification Ministry in Seoul said no particular signs have emerged in exchanges and cooperation between the two Koreas, citing that the North’s survey of real estate held by South Korean companies at the Mount Geumgang resort is proceeding smoothly and that cross-border passage is normal.