The Venezuelan opposition leader Juan Guaido has said intelligence agents arrested his chief of staff after a pre-dawn raid, signalling that president Nicolas Maduro may be cracking down on the opposition's challenge to his rule.

Mr Guaido invoked the constitution in January to assume the interim presidency after declaring Maduro's 2018 re-election a fraud, and has been recognised by dozens of Western nations as the country's legitimate leader.

Mr Maduro, who has overseen a dramatic collapse of the country's economy, has called Mr Guaido a puppet of the United States and said he should “face justice”, but has not explicitly ordered his arrest.

“They have kidnapped @ROBERTOMARRERO, my chief of staff,” Mr Guaido said in a post on Twitter.

He also said the Caracas residences of Mr Marrero and opposition legislator Sergio Vergara had been raided before dawn.

Venezuela aid protests: Civilians demand food and medicine Show all 5 1 /5 Venezuela aid protests: Civilians demand food and medicine Venezuela aid protests: Civilians demand food and medicine Demonstrators push a bus that was torched during clashes with the Bolivarian National Guard AP Venezuela aid protests: Civilians demand food and medicine Demonstrators are seen through the cracked windshield of a torched bus AP Venezuela aid protests: Civilians demand food and medicine A woman moves away from the flames of a burning bus AP Venezuela aid protests: Civilians demand food and medicine A bus that was torched during clashes with the Bolivarian National Guard AP Venezuela aid protests: Civilians demand food and medicine Demonstrators push away a bus that was torched during clashes AP

“We do not know their whereabouts. They should be freed immediately,” he added.

Venezuela's Information Ministry did not immediately respond to a request for comment.

Mr Guaido travelled around South America in February to drum up diplomatic support for his government, defying a travel ban imposed by the pro-government Supreme Court.

He re-entered the country via Venezuela's principal airport without being detained by immigration officials.

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Dozens of countries including the United States, major European powers and most South American nations have backed Mr Guaido and say Mr Maduro's rule is illegitimate.

Venezuela is reeling from annual inflation topping 2m per cent, which has fuelled malnutrition and preventable disease and spurred an exodus of more than 3m citizens since 2015.

Mr Maduro says his government is the victim of an “economic war” led by his political adversaries and blames US financial and oil sector sanctions for the country's situation.