Venezuelan opposition leader Juan Guaido’s deputy has been detained by the country’s intelligence services in a dramatic operation in eastern Caracas.

The arrest of Edgar Zambrano, Vice President of the National Assembly, took place on Wednesday night. He is the first senior opposition official taken into custody by the socialist government in retaliation for a failed military uprising last week aimed at ousting embattled President Nicolas Maduro.

Zambrano live-tweeted the detention, saying his van was surrounded by forces from Venezuela’s Bolivarian Intelligence Service (Sebin). When he refused to exit, Zambrano said, his vehicle was forcibly towed to the infamous Helicoide prison, a notorious holding area for political prisoners.

The move came after Zambrano became one of 10 opposition officials charged with treason, conspiracy and rebellion by the pro-Maduro Supreme Court in connection to the April 30 plot.

So far, the leader of the uprising — Guaido, who has been recognized as “interim President” of Venezuela by over 50 countries, including the US, the UK and most in Latin America — has not been charged.

Guaido says he remains a free man because the government of Maduro is “too afraid” of the consequences of arresting him. “Because they’re scared. Those that try to spread or generate a perception of control are the ones that don’t have it,” he told CNN.

Maduro, on the other hand, has the backing of Russia, China and the leaders of Venezuela’s military.

Zambrano’s detention drew swift condemnation from the US. It threatened unspecified “consequences” if the leader was not released.

“The arbitrary detention of @AsambleaVE First VP Edgar Zambrano by Maduro’s oppressive security forces in Venezuela is illegal and inexcusable,” read a tweet issued by Kimberly Breier of the US Embassy in Caracas.

Though the US administration appears to be conflicted over using force to drive Maduro out, it has not ruled out a military option.

Through stripped of its power in 2017, the opposition-controlled National Assembly is widely recognized internationally as the only democratic institution left in Venezuela, making Zambrano the second-highest opposition figure in rank after Guaido, who is the body’s President.

Guaido’s Chief of Staff, Roberto Marrero, has been in prison since March 21, when his house was raided before dawn by armed intelligence forces.

In the past week, the socialist government detained 82 street protesters, according to Foro Penal — a non-profit legal group that defends and denounces political imprisonments.

Three hundred people have been injured at protests, including 40 that have been struck by bullets, and four killed.