The State Department's call came days after the Venezuelan Supreme Court upheld the punishment of Leopoldo Lopez, who is serving a nearly 14-year sentence on charges of inciting unrest at anti-government protests in 2014.
"We call for the immediate release of all prisoners of conscience, respect for the rule of law, the freedom of the press, the separation of constitutional powers within the government, and the restoration of a democratic process that reflects the will of the Venezuelan people," the department's acting spokesman Mark Toner said in a statement.
"The United States reiterates its dismay and concern about these arrests, and other actions taken by the Venezuelan government to criminalize dissent and deny its citizens the benefits of democracy," the statement said.
The ruling on Lopez's appeal, which was filed in July, came a day after Trump received Lopez's wife Lilian Tintori at the White House and posted a tweet calling for the prisoner's release.
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"Venezuela should allow Leopoldo Lopez, a political prisoner & husband of @liliantintori (just met w/ @marcorubio) out of prison immediately," Trump tweeted following the meeting.
Some 200 Venezuelan opposition supporters marched today, blocking one of the main highways in Caracas to protest Lopez's imprisonment.
Shortly before Trump sent his Twitter missive this week, Maduro had warned the US that Venezuela would "respond firmly" to any action deemed aggressive.
"Those who tangle with us will get an appropriate response," he said on state television.
Ties had already been strained on Monday when the US Treasury imposed sanctions on Maduro's powerful Vice President Tareck El Aissami and a businessman, whom the US authorities accuse of being involved in drug trafficking.
The former Venezuelan president was famous for his anti-American rhetoric, which has persisted under Maduro, who blames his country's deep economic woes on a US-backed capitalist conspiracy.
The two countries have not swapped ambassadors since 2010, but do share important economic relations, especially in the oil sector.