WASHINGTON, DC, United States (AFP) — Marco Rubio headed to Panama Saturday on his début trip abroad as US secretary of state, as he looks for how to follow up on President Donald Trump’s extraordinary threat to seize the Panama Canal.

Rubio’s mission came as Trump imposed steep tariffs on Canada, Mexico and China — another step showing a far more aggressive US foreign policy.

Rubio will travel later to four other small Latin American countries for an agenda focused on migration, a highly unusual first trip for the top US diplomat, whose predecessors were more likely to start the job with language of cooperation with major allies.

Trump has refused to rule out military force to seize the Panama Canal, which the United States handed over at the end of 1999, saying that China has exerted too much control through its investment in surrounding ports.

In his inaugural address, Trump said that the United States will be “taking it back” — and he refused to back down Friday.

“They’ve already offered to do many things,” Trump said of Panama, “but we think it’s appropriate that we take it back.”

He alleged that Panama was taking down Chinese-language signs to cover up how “they’ve totally violated the agreement” on the canal.

“Marco Rubio is going over to talk to the gentleman that’s in charge,” Trump told reporters.

Rubio did not comment on his trip as he boarded his plane to Panama.

Panamanian President Jose Raul Mulino, generally considered an ally of the United States, has ruled out opening negotiations after complaining to the United Nations about Trump’s threat.

“I cannot negotiate, much less open a process of negotiations on the canal,” Mulino said Thursday.

The issue “is sealed. The canal is Panama’s,” Mulino said.

Mulino’s Government, however, has ordered an audit of CK Hutchison Holdings, the Hong Kong company that operates ports on both sides of the canal.