CARACAS (Reuters) - Venezuela late on Friday freed an 85-year-old activist, who is the sole survivor of a clandestine group that fought a 1950s military dictatorship, after he was detained by intelligence agents for a day.

The family of lawyer Enrique Aristeguieta and the political party Justice First said he was taken from his home in Caracas in the early hours of Friday, with no explanation from authorities.

“Full freedom for Enrique Aristeguieta and we’ll also achieve that for Venezuela,” said hard-line opposition leader Maria Corina Machado.

Aristeguieta is an outspoken opposition campaigner who regularly compares what he calls the “narco-tyranny” of socialist President Nicolas Maduro to the 1952-1958 dictatorship of Marcos Perez.

Aristeguieta’s Twitter feed had not yet been updated and the last message posted at about 4 a.m. Friday said he was being sought by Venezuelan intelligence agents in his home.

Authorities did not respond to a request for comment earlier on Friday on the detention.

Local rights group Penal Forum said Aristeguieta was one of 14 activists rounded up during the past week, among about 200 who are being detained by the Maduro government.

Critics say the ruling Socialist Party persecutes dissenters while officials insist they are acting legitimately against people plotting against the government with U.S. support.