A military intervention to oust Venezuelan strongman Nicolás Maduro remains “a very serious option” for the United States, according to President Trump’s national security team.

“Obviously, that’s a result that no one would like to see but clearly one that is seriously considered as events unfold,” a senior administration official, speaking on condition of anonymity, told reporters Friday evening.

President Trump’s team has wielded that threat to deter any attack by Maduro loyalists on Juan Guaidó, the opposition lawmaker whom the U.S. and other Western democracies recognized as Venezuela’s legitimate interim president in January. Maduro has defied that pressure by retaining control of the military and loyalty of "colectivos," the paramilitary gangs that blocked the U.S. delivery of humanitarian aid to the country in February.

“We hope that the military will uphold its constitutional duty to protect the Venezuelan people from these illegal terrorist groups known as the colectivos which Maduro is increasingly dependent on,” the senior administration official said.

That unofficial labeling of the colectivos as “terrorists” appears to be part of a broader effort in U.S. tactics against Maduro. Sen. Marco Rubio, R-Fla., wants President Trump to put both the Maduro regime and the colectivos on the official list of foreign terrorist organizations, alongside groups such as ISIS and al Qaeda.

“The truth is the Maduro regime built up this network of colectivos as its own private security force to protect its grip on power and violently resist any effort to dislodge it from power,” Rubio said.

The Florida Republican might already have an ally in Vice President Mike Pence, who warned earlier Friday that “narco-trafficking, terrorists, criminal syndicates that emanate from a collapsing society in Venezuela endanger nations throughout our hemisphere.”

The intensifying rhetoric comes just two weeks after Luis Almagro, the secretary-general of the Organization of American States and the original international scourge of Maduro, argued that world powers have a “responsibility to protect” the Venezuelan people from the regime.

The discussions are unfolding as U.S. officials acknowledge that Maduro has proven unexpectedly resilient, due in part to support from Cuba and Russia.

“We’re thinking about the Russian presence very seriously and its ramping up and the growing complicated nature of Venezuela,” Kiron Skinner, the State Department director of policy planning, said Wednesday. “This is not an easy off-ramp for Maduro, as some would have hoped.”