Venezuelan Opposition leader Juan Guaidó said on Thursday that intelligence agents had detained his Chief of Staff following a pre-dawn raid, signalling that President Nicolás Maduro may be cracking down on the Opposition’s challenge to his rule.

U.S. Secretary of State Mike Pompeo, in a post on Twitter on Thursday, called for Roberto Marrero’s immediate release and said “we will hold accountable those involved”.

“They have kidnapped @Robertomarrero, my Chief of Staff,” Mr. Guaido said in a post on Twitter, adding that the Caracas residences of Mr. Marrero and Opposition legislator Sergio Vergara had been raided before dawn. “Look after the President,” Mr. Marrero said in a voice message sent to reporters by Mr. Guaido’s press team, as he reported that agents were trying to enter his house.

The press team also sent a video of another Opposition lawmaker showing damage to the door of Marrero's home and a broken lock.