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.

The Tuesday hearing delved into security issues and foreign influence on the foremost maritime channel connecting the Atlantic and Pacific Oceans.

China's influence on the Panama Canal is a major risk to U.S. national security, Sen. Ted Cruz told lawmakers during a Senate hearing on Capitol Hill.