Washington remains open to dialogue with Pyongyang but is not convinced the DPRK is “credible,” Secretary of State Rex Tillerson said on Tuesday, while declining to comment on reports that the U.S. is preparing for military action against North Korea.

Speaking at a joint conference with Canada’s foreign affairs minister Chrystia Freeland following the Meeting on Security and Stability on the Korean Peninsula in Vancouver, Tillerson said the U.S. is “open to serious negotiations.”

“North Korea knows our channels are open and the way to find us,” the Secretary of State said. “Productive negotiation requires a credible negotiating partner. North