Masked security forces detained a key aide to Venezuelan opposition leader Juan Guaidó in a raid on his home early Thursday, arriving in a convoy of vehicles and breaking down his door in a show of force that escalated tensions with the United States. Lawyer Roberto Marrero was taken away by intelligence agents in an overnight operation that was promptly condemned by Guaidó as well as U.S. Secretary of State Mike Pompeo, who called for the immediate release of the opposition figure.

"We will hold accountable those involved," Pompeo tweeted. The U.S. has imposed oil sanctions on Venezuela as well as individuals linked to President Nicolás Maduro in an attempt to force him from power.

President Trump has said tougher sanctions could occur and that "all options are on the table," a remark that Maduro and his ally, Russia, have interpreted as a possible prelude to military intervention. The Venezuelan government had no immediate comment on Marrero's detention, which represented a sharp increase in police pressure on the opposition after a period of relative calm.

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Guaidó had even said that the government was ignoring him in an attempt to sap the energy of the opposition, though Maduro has often described his adversary as a "puppet" and a "clown." Marrero reported the raid in a telephone call whose recording circulated on social media soon after the operation occurred.

As he described how a large group of intelligence officials was entering his home, heavy thuds could be heard in the background. The neighboring home of opposition lawmaker Sergio Vergara was also searched.

Vergara said he was woken up by heavy banging at his door and that agents pointed weapons at him. The security forces broke through a metal screen door and a wooden door to get into Marrero's house and left drawers open during their search, said Carlos Berrizbeitia, another opposition lawmaker who later visited the residence.

Damage is seen at the residence of Roberto Marrero, chief of staff to opposition leader Juan Guaido, after he was detained by Venezuelan intelligence agents, according to legislators, in Caracas, Venezuela, March 21, 2019. Reuters/Ivan Alvarado

Dozens of security forces were involved. Vergara and Marrero both accompanied Guaidó on a recent Latin American tour to build international support for his efforts to oust Maduro.

Marrero heads the office of Guaidó, who is leader of Venezuela's National Assembly. "We don't know where he is. He should be freed immediately," Guaidó tweeted.

The opposition leader, who had defied a travel ban to leave the country, returned to Venezuela on March 4. The United States had warned the Venezuelan government against taking action against Guaidó, who has staged frequent demonstrations in an attempt to remove Maduro.

Venezuelan prosecutors said Guaidó is under investigation for alleged links to violence as well as the nation's worst power outages. Maduro alleges the blackouts were caused by U.S.-directed sabotage, though U.S. officials and the Venezuelan opposition said state mismanagement and corruption caused the infrastructure collapse.

The U.S. and about 50 other countries support Guaido's contention that he is the rightful leader of Venezuela and that Maduro's re-election last year was illegitimate. Maduro said Guaido is a collaborator in a U.S. plot to overthrow his government.

Earlier this week, Robert Palladino, a U.S. State Department spokesman, said Guaidó's government had assumed control of three Venezuelan diplomatic facilities in the U.S. They included two military attache buildings and the Venezuelan Consulate in New York.