Secretary of State Marco Rubio is traveling to Central America on Saturday, kicking off his first official trip with a visit to Panama amid tensions over President Trump’s threats to seize control of the Panama Canal.

Mr. Rubio’s plan to visit four Central American nations, along with the Dominican Republic, reflects the Trump administration’s intense focus on halting illegal immigration across the U.S.-Mexico border, as well as the influence migration will have on American diplomacy in the coming years. Mr. Rubio’s other planned stops are El Salvador, Guatemala and Costa Rica.

The itinerary also follows Mr. Rubio’s longstanding interest in Latin America. The son of Cuban immigrants, Mr. Rubio was a Republican leader on U.S. policy toward the region during his Senate career.

The trip’s highlight is likely to be Mr. Rubio’s visit to Panama, which will include a stop at the Panama Canal, State Department officials said. That sets up a potentially tense dynamic with Panamanian leaders, who say they are unwilling even to discuss transferring control of the canal.

Mr. Trump has repeatedly said that he wants to reclaim control of the canal, a vital shipping lane built and administered by the United States in the early 1900s. Mr. Trump and Mr. Rubio have cited the presence of Hong Kong-based companies near the canal’s entrances as a strategic threat, suggesting that China could use them to shut it down.

In an interview on Thursday with the conservative host Megyn Kelly, Mr. Rubio said the president’s interest in the canal was quite serious and would be a main topic of conversation during his visit to Panama City despite strong opposition there to relinquishing control of the waterway.