The United States is intensifying diplomatic and military manoeuvres to challenge Panama's sovereignty over the strategically crucial Panama Canal, with Washington developing contingency plans that range from increased military cooperation to potential forceful intervention.

Donald Trump has said repeatedly that he wants to “take back” the Panama Canal but has not offered specifics about how he would do so. Here is an explanation of the history and laws governing the critical waterway.

Potential plans range from partnering more closely with Panamanian security forces to a less likely option of U.S. troops' seizing the canal by force, U.S. officials told NBC News.