Washington and Moscow have over decades established mechanisms to prevent crises from spinning out of control, from hot-lines to satellites and over-flights that allow the nuclear-armed adversaries to track each other's military deployments.
No such safety nets exist between Washington and Pyongyang, worrying experts who say an accident, misstatement or erroneous reading by one side of the other's actions could spiral into full-scale conflict even though neither side wants war.
Tensions between the two countries have risen markedly in the last few days after North Korea warned Washington of a "severe lesson" following U.N. action against it and U.S. President Donald Trump in turn warning that any threats to the United States from Pyongyang would be met with "fire and fury."