Erik Prince, founder of the private security firm Blackwater and prominent supporter of Donald Trump, made a secret visit to Venezuela last month and met Vice-President Delcy Rodríguez – one of Nicolás Maduro’s closest allies.

The visit, described by one source as “outreach” to Maduro’s government, came just eight months after Prince floated a plan to deploy a private army to help topple the Venezuelan leader.

It was unclear what Prince, the brother of Trump’s education secretary, Betsy DeVos, discussed with Rodríguez. The meeting was first reported by Bloomberg.

A meeting with Rodríguez, who is under US sanctions, could raise questions about whether Prince might have run afoul of US law, which prohibits Americans from virtually any business dealings with sanctioned individuals and specifically with the Venezuelan government. The Venezuelan vice-president’s office also oversees the country’s national intelligence service.

Prince informed one White House official of the planned meeting ahead of his trip, but it was not known whether he asked for approval or advice, according to one of the sources.

The White House declined to comment when asked if US officials had advance word of Prince’s visit or whether it was seen as a possible line of communication with the Maduro government. In January, Washington recognized the opposition leader Juan Guaidó as the Opec nation’s legitimate president and began ratcheting up sanctions and diplomatic pressure in an effort to oust Maduro.

Prince’s spokesman, Marc Cohen, declined to comment. Rodríguez did not respond to questions via text message. Her brother, the information minister, Jorge Rodríguez, also did not respond to a request for comment.

Five sources told Reuters that Prince, a businessman known for his rightwing views, visited Caracas around 20 or 21 November and met Rodríguez, a leader of Venezuela’s ruling socialist party who was appointed as vice-president by Maduro last year.

“It was something more than a private business trip,” one Venezuelan source in Washington who has contacts with both the opposition and Maduro’s government said.

Delcy Rodríguez gives a clenched-fist salute alongside Venezuela’s President Nicolás Maduro in Caracas in January. Photograph: Luis Robayo/AFP/Getty Images

The United States and more than 50 other countries have recognized Guaidó, head of the opposition-controlled national assembly, as interim leader after he invoked the constitution to assume a rival presidency in January, arguing Maduro’s 2018 re-election was a sham.

Maduro retains the support of the military and of international allies including Russia, China and Cuba.

US sanctions imposed in August bar most US citizens or companies from doing business with the Venezuelan government. Rodríguez, who has travelled the world seeking to shore up what remains of Maduro’s backing abroad, was hit with sanctions by the treasury department in September last year.

It described her as member of Maduro’s inner circle who helped him “maintain power and solidify his authoritarian rule”.

Peter Kucik, a former expert at Treasury’s Office of Foreign Assets Control, which enforces US sanctions, said such a meeting would run the risk of violating US regulations if they “went beyond casual conversation, entered into an agreement”.

“The more substantive the discussion, the more likely you have a problem,” Kucik said.

Prince’s meeting with Rodríguez represents a surprising twist for a businessman with long experience of trying to privatize warfare.

In April, Reuters reported that Prince had proposed using a private army of 5,000 mercenaries to topple Maduro.

There is no sign that Prince’s plan ever advanced beyond an early discussion stage.

Prince has been accused of acting as a back channel on behalf of Trump before. As Trump was preparing to take office in 2017, Prince met with an official close to Vladimir Putin in the Seychelles, islands off the coast of east Africa. Special counsel Robert Mueller’s report on his Russia investigation said the meeting was set up with the knowledge of the former White House aide Stephen Bannon.

Blackwater sparked international outrage in 2007 when its employees shot and killed 17 Iraqi civilians in Baghdad. One of the employees involved was convicted of murder in December and three others were convicted of manslaughter.