The mayor of Caracas, Venezuela, was arrested Thursday, accused of plotting a coup against the government.

Venezuelan President Nicolás Maduro made the claim in nationally televised address where he blamed the U.S., who he said wants him removed from power.

In Washington, the State Department flatly rejected Maduro’s charges, saying they are “baseless and false.”

“The United States is not promoting unrest in Venezuela nor are we attempting to undermine Venezuela’s economy or its government,” State Department spokeswoman Jen Psaki said in a statement. “The Venezuelan government should stop attempting to distract attention from the country’s economic and political problems and focus on finding real solutions through democratic dialogue among Venezuelans.”

Sources told the Noticias24 news portal that masked SEBIN agents arrested Antonio Ledezma at his office and led him away by force at around 5 p.m. local time (GMT2130).

Richard Blanco, a Venezuelan lawmaker who shares office space with Ledezma said heavily-armed agents entered the room and beat him and the mayor, while refusing to produce an arrest warrant.

Alfredo Jimeno, alderman of the Caracas municipality of Chacao, a key flashpoint in the deadly 2014 anti-government protests, also told NTN24 news that when attempts were made to stop the arrest, one of the agents fired into the air.

Ledezma has been one of Maduro’s fiercest critics, along with imprisoned opposition leader Leopoldo López and former deputy María Corina Machado, who quickly took to Twitter to decry the mayor’s detention.

Machado has ramped up her attacks on the Maduro government in recent weeks.

Ledezma was recently accused of being involved in a planned coup against Maduro, who has repeatedly alleged similar plots against him, and more recently announced several members of the country’s Air Force had been arrested in connection with one such attempt.

Freddy Guevara of the Voluntad Popular, or Popular Will, opposition party, characterized Ledezma arrest as “senseless” and demanded his release, adding that “the government has to assume responsibility for this case,” NTN24 reported.

There were also reports Thursday of a disturbance at the Ramo Verde military prison, located outside Caracas, where López, who led the Voluntad Popular party, is being held.

López’s wife, Lilian Tintori, tweeted that guards attempted to “abduct” her husband as a riot allegedly took place at the prison.

Tensions had already rose in Caracas on Wednesday as members of the opposition marked a year since López surrendered to face charges of inciting violence as anti-government protests rocked the country in the first half of 2014.

Psaki also backed calls for Caracas to release Lopez.

At least 43 people died, on both sides of the political divided, in the ensuing three months of demonstrations, which were initially called to highlight startling levels of violence, the ongoing muzzling of non-government-aligned media, and shortages of staple products.

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