Washington's sanctions on Jorge Arreaza and Judge Carol Bealexis Padilla de Arretureta freeze any assets they have in the US. Meanwhile, Venezuela's opposition-run National Assembly says a lawmaker has been illegally detained.
The Trump administration added the Venezuelan foreign minister to a Department of Treasury sanctions target list in an attempt to increase pressure on embattled President Nicolas Maduro.
A US statement issued on Friday says Foreign Minister Jorge Arreaza along with a judge have been added to a growing list of Venezuelan officials designated for sanctions by the treasury department.
The designation of Arreaza and Judge Carol Bealexis Padilla de Arretureta freezes any assets they have in the United States and prohibits any US citizens or entities from having any financial dealings with them.
The move is part of an effort by the Trump administration to press Maduro to leave office amid a deep political and economic crisis.
Juan Guaido, the opposition-run National Assembly leader, has mounted a challenge to Maduro, arguing his 2018 re-election was illegitimate. Guaido in January invoked the country's constitution to assume an interim presidency.
He has been recognised as Venezuela's rightful leader by most Western countries, including the US.
The opposition said those accusations were false.
Opposition-run lawmakers detained in Venezuela
The National Assembly said on Friday that opposition lawmaker Gilber Caro had been detained, which it said in a Twitter post was a violation of his parliamentary immunity.
Caro spent a year and a half in jail before being freed in June 2018.
Neither Venezuela's information ministry nor the chief prosecutor's office immediately responded to requests for comment on Caro's detention.
He had previously been jailed along with hundreds of other activists involved in protests against Maduro, according to human rights groups.
Earlier this month, Venezuela's Constituent Assembly – an all-powerful legislature controlled by the governing Socialist Party and whose powers supersede those of the Assembly – approved a measure allowing for a trial of Guaido, who as a legislator also has parliamentary immunity.
Venezuela's chief prosecutor's office has opened an investigation of Guaido into alleged links to "incidents of violence" in January but has not ordered his detention or officially charged him with any crime.
In March, Venezuelan authorities detained Guaido's top aide, Roberto Marrero, accusing him of planning attacks against top political figures.