WASHINGTON (Reuters) - 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.

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.

The new administration's immigration crackdown is likely to be among the top issues during talks, but US President Donald Trump's claim that the Central American nation had ceded control of the Panama Canal to China will also loom large.

The neutrality of the nearly 50-mile canal, through which nearly 15,000 ships transit each year, is enshrined in Panama’s Constitution and is enforced by the autonomous Panama Canal Authority.

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,

Secretary of State Marco Rubio says President Donald Trump’s desire to acquire Greenland and retake control of the Panama Canal is driven by legitimate national security interests stemming from growing concerns about Chinese activity and influence in the Arctic and in Latin America.