The move highlighted strained diplomatic relations between the United States and the leftwing government of Venezuelan President Nicolas Maduro.
Neither country has had ambassadors in the other for the past six years.
According to a statement on the US embassy website, from yesterday no more interviews will be conducted for new applicants seeking tourist or business visas to visit the United States.
Those renewing visas or applying for immigrant or investor visas can still do so, but some will face longer than usual wait times, it added.
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It said US State Department technicians had also been prevented from visiting to maintain the mission's consular computer systems.
The situation, it said, had resulted in a huge backlog of visas to be handled.
"As soon as the foreign ministry resumes issuing visas... we will resume complete services to the Venezuelan public."
Contacted by AFP, the Venezuelan foreign ministry did not immediately comment on the embassy's statement.
His predecessor, the late Hugo Chavez, also accused the US of mounting conspiracies against him, and alleged that America might have injected him with the cancer that ended up killing him in March 2013.
Before the change, thousands of Venezuelans lined up each week at the US embassy in Caracas to apply for visas, with Florida the preferred travel destination.
Venezuela's slide into economic disaster, with three years of brutal recession and runaway inflation, has spurred emigration.