Secretary of State Marco Rubio said on Thursday he had "zero doubt" that China has a contingency plan to shut down the Panama Canal in the event of a conflict with the U.S. and that Washington intends to address what it sees as a national security threat.

A key focus of Secretary of State Marco Rubio’s visit to Central America this week — his first trip as America’s top diplomat — will be to counter China’s growing influence in the region, the State Department’s top spokesperson said this week,