State Department director of policy planning Brian Hook said Secretary of State Rex Tillerson would be looking for help developing "practical mechanisms" to pressure Pyongyang.
Secretary of State Rex Tillerson will head to Canada next week to co-host a meeting of high-level worldwide diplomats focused on expressing solidarity against 's ongoing nuclear weapons and ballistic missile provocations.
It will be joined mainly by the 16 nations that fought alongside or provided combat support to the South in the 1950-53 Korean War. In addition, he suggested that the Security Council should add to the list of vessels that are explicitly banned from worldwide ports for suspected sanctions violations. According to a Russian expert, who visited Pyongyang recently and spoken to senior North Korean figures, the overall mood at the Kim Jong-un regime suggests there is no doubt on whether a full-fledged conflict will break out.
Analyst Mark Valencia, a researcher at China's National Institute for South China Sea Studies, warned previous year that attempts to authorize high-seas interdictions would essentially legalize an act of war - an opposed boarding of another flag state's vessel - and potentially undermine the principle of freedom of navigation.
Some countries, even friends of the United States, may be concerned that such methods could increase military tensions or be interpreted as an act of war by the isolated North.
While China has rejected calls from past presidents to do more, Beijing is starting to go along with US initiatives to put pressure on North Korea, even accepting USA demands for restrictions on oil exports to the North.
It is unclear whether Pyongyang has also initiated conversations with the United States.