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.

Rubio said he could not predict if Trump would succeed in buying Greenland from Denmark or restoring American authority over the Panama Canal while he is in office.

President Trump is reportedly dispatching his newly confirmed Secretary of State Marco Rubio to Panama for his first foreign trip. Here's what's at stake.

Trump's new top maritime official Louis Sola tells CNBC 'all options on the table' to punish Panama and defend U.S. business, trade and national security.

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.

Panama has owned and administered the Panama Canal for nearly three decades. President Trump wants to change that to counter growing Chinese influence in Latin America.

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

US senators heard sharply different analyses about Chinese influence over the Panama Canal on Wednesday, with some experts suggesting solutions ranging from enhanced trade partnerships to military intervention to regain control of the strategic waterway.

Secretary of State Marco Rubio declared Thursday that President Trump’s interest in taking control of Greenland and the Panama Canal “is not a joke” and vital to US national security interests. “This is not a joke,

Trump could make history by leading the charge for Puerto Rican statehood. He would achieve many of the same goals behind his push for Canada, Greenland and the Panama Canal.

Secretary of State Marco Rubio asserts that President Trump's interest in acquiring Greenland and reasserting control over the Panama Canal stems from legitimate national security threats posed by China's growing influence in these strategic areas.