Secretary of State Marco Rubio embarks soon on his inaugural trip as the United States’ top diplomat. His first stop, Panama could prove to be the most contentious on the itinerary.

Russia warned President Trump on Tuesday against seizing the Panama Canal, after he reiterated his intent to take control of the strategic waterway in his second inaugural address Monday. “We expect that during the expected discussions between the leadership of Panama and US President Donald Trump on issues of control over the Panama Canal,

Trump has repeatedly threatened to take ownership of the critical maritime trade route — which the U.S. signed over to Panama in 1977 — calling it “vital” to American interests and refusing to rule out using military force in pursuit of his goal.

Panama's President Jose Raul Mulino has ruled out negotiations with the US over ownership of the Panama Canal as he prepares to Marco Rubio.