Guaidó, who has declared himself the nation’s interim president, was briefly detained early in the effort. But thus far, the government, facing stern warnings from Washington, has exercised restraint in dealing with him and his inner circle.
Yet the detention Thursday of Roberto Marrero, 49, suggests an important and potentially dangerous shift toward more-aggressive tactics. In a statement suggesting serious charges, Maduro’s interior minister, Néstor Reverol, claimed Marrero was part of a “terror cell” plotting against the government. He said authorities had identified a “bigger group” of suspects and were searching for them and a cache of weapons.
Marrero “is directly responsible for these criminal groups,” Reverol said. He said that “war weapons and money in cash were found” during the raid.
The opposition said that the weapons were planted and that the terrorism charges are a fiction. U.S. officials quickly condemned the detention of Marrero.
The arrest suggests a wider crackdown on dissent. Maduro’s government has detained dozens of journalists in recent months. Many have been quickly released, but at least one remains in jail. The government has also arrested two workers from the state utility who denounced the poor state of the power grid, which suffered in a nationwide blackout this month.
“The United States condemns raids by Maduro’s security services and detention of Roberto Marrero,” Secretary of State Mike Pompeo tweeted. “We call for his immediate release. We will hold accountable those involved.”
The United States and more than 50 other countries have recognized Guaidó, the president of the National Assembly, as Venezuela’s rightful leader.
Guaidó urged the opposition to increase pressure on the government in response to the detention. But he did not outline specific steps.
“I call the people to double or triple efforts if necessary,” he said. “Since they can’t take the president to jail, they seek to threaten and kidnap those close to him.”
He warned Maduro’s government that the “international community is watching.”
“We are in direct communication with them,” he said. “We do have very powerful allies in the world that are willing to help.”
The home of opposition official Sergio Vergara, a neighbor of Marrero’s, was also raided. Vergara claimed that the intelligence service, known as the SEBIN, had planted weapons, including a grenade, at Marrero’s home.
Vergara said the raiding party — 15 armed men wearing caps — entered his home and held him down on the floor as they searched his apartment.
“They asked me if I knew where Roberto Marrero lived, which I didn’t respond to,” he said in a video on Twitter.
During the raid on his home, Marrero recorded a voice message that circulated on social media. “In this moment, the SEBIN are in my house,” he said. “They, sadly, came for me. Keep fighting. Don’t stop. Please take care of the president. And let it be what God wants. God bless you.”
Vergara’s driver, Luis Aguilar, was also detained, Guaidó spokesman Edward Rodríguez said.
Opposition websites showed images of Marrero’s ransacked apartment after the raid. The entrance door appears broken, dresser drawers are open and their contents — sheets, children’s toys, boxes and folders — are strewn about the floor.
Vergara said he saw Marrero before he was taken away.
“Marrero shouted at me that they had planted two rifles and one grenade,” he said. “The men told him to shut up. I told him to be strong.”
In addition to serving as Guaidó’s chief of staff, Marrero was the longtime lawyer of opposition leader Leopoldo López, Guaidó’s mentor.
López was detained in 2014 and remains under house arrest.
“The government is closing Guaidó’s circle, measuring reactions domestically and abroad,” said political analyst Félix Seijas, director of the Delphos polling agency in Caracas. “And sending a message: We are still here.”
The Trump administration has warned Maduro against acting directly against Guaidó. U.S. officials have threatened unspecified consequences if he does.
The United States already has slapped strict sanctions on Maduro’s government, effectively cutting off its biggest single source of cash: oil sales to the United States.
But Sen. Marco Rubio (R-Fla.) said Washington can do more.
“There are more places to hit, more people to go after, as the noose tightens for them,” Rubio said. He said the United States would consult with allies such as Spain that have served as safe harbors for family members of Maduro government officials.
The Venezuelan opposition has been seeking to regain momentum in its effort to force Maduro from office.
Guaidó led an effort last month to push humanitarian aid, largely from the United States, into the country. Maduro sent soldiers to the borders to block the food, medicine and supplies. Guaidó had hoped the soldiers would defy Maduro’s orders and join the opposition.
That mostly did not happen. But the effort helped focus international attention on the plight of Venezuelans. A failing power grid has caused massive blackouts, and a broken economy has left millions struggling with shortages of food and medicine.
Guaidó has won the backing of dozens of countries, leaving Maduro increasingly isolated. After a rupture in diplomatic relations, the United States withdrew the last of its diplomats from Caracas this month.
Faiola reported from Miami.