Erik Prince, a major Republican donor and founder of controversial security firm Blackwater, has been referred to the U.S. Treasury Department for possible sanctions violations tied to his recent trip to Venezuela for a meeting with a top aide of President Nicolas Maduro, two senior U.S. officials said.

There's no indication that Prince, whose sister is Education Secretary Betsy DeVos, will be sanctioned for the meeting last month in Caracas with Venezuela's Vice President Delcy Rodriguez.

But the fact the visit was flagged underscores the concern of officials in the Trump administration over what appeared to be anunauthorized diplomatic outreach to Maduro. This, as support for opposition leader Juan Guaidó inside Venezuela — if not Washington — appears to be waning.

The U.S. officials spoke on the condition of anonymity because they aren't authorized to discuss the matter publicly.

Little has been revealed about Prince's surprise trip to Caracas last month. But the mere presence in Venezuela of a businessman with longstanding ties to the U.S. national security establishment prompted questions about whether he was there to open a secret back channel to Maduro on behalf of the Trump administration, something the State Department has strenuously denied.

It also marks something of a reversal for Prince, who earlier in 2019 was thought to have been pitching a plan to form a mercenary army to topple Maduro.

A person familiar with Prince's visit said he had been asked to travel to Venezuela by an unidentified European businessman with longstanding ties to the oil-rich nation. The person said Prince did not discuss any business nor receive anything of value during his trip — actions that would've violated U.S. financial sanctions on Maduro's socialist government.

The purpose of the trip was to meet key players in the crisis-wracked nation, not to serve as an emissary for the Trump administration, according to the person, who isn't authorized to discuss the visit and spoke on condition of anonymity.

The person said Prince, a former Navy SEAL, continues to support the Trump administration’s goal of removing Maduro but believes State Department efforts to reach that goal have failed and new alternatives — which the person did not specify — need to be tried.

Before traveling, Prince notified the National Security Council and Treasury Department about his plans and received no objections, the person said.

In a statement, Prince's attorney didn't provide any details about the trip or whom his client may have alerted in the U.S. government.

“Before traveling to Venezuela as a private citizen, Erik Prince received clear legal guidance, which he scrupulously followed,' Matthew Schwartz said in the statement. 'There is nothing unlawful about simply visiting Venezuela and participating in non-business discussions, which is all that Mr. Prince did. We would be better served by focusing on measures that might actually restore peace and prosperity to Venezuela rather than worrying about who paid a visit to whom.'

Neither the National Security Council nor the Treasury Department responded to a request for comment.

Rodriguez is a key aide to Maduro and also one of more than 100 Venezuelan government insiders who have been slapped with sanctions by the U.S. In addition, the Trump administration this year has imposed sweeping sanctions on Venezuela's oil industry and a ban on U.S. companies and individuals from doing business with the Maduro administration.

While in Caracas, Prince also met members of the opposition, although the person familiar with his trip declined to say whom.

An aide to Juan Guaidó said no such meeting with anyone in the opposition took place. But the aide was unable to provide the same assurances for a small faction of minority parties that recently split from Guaidó and initiated negotiations with Maduro that the U.S. considers a time-wasting sideshow.

A year after the U.S. recognized Guaidó as Venezuela's interim president, arguing that Maduro's re-election was fraudulent, the 36-year-old lawmaker is under increasing pressure from friends and foes alike to articulate a fresh vision for unseating the socialist leader, who has grown more confident as the economy stabilizes under a flood of black-market U.S. dollars.

Another person familiar with the visit said Prince, in his late November dinner at Rodriguez’s home, urged the release of six executives of Houston-based Citgo held for more than two years on what are widely seen as trumped-up corruption charges. Two weeks later, the six men — five of them dual U.S.-Venezuelan citizens — were granted house arrest. The person also spoke on the condition of anonymity given the sensitivities surrounding the trip.

Elliott Abrams, the U.S. special envoy to Venezuela, said Dec. 20 that Prince was not a messenger for the U.S. government, nor was the U.S. engaging in any secret talks with Maduro.

“I have yet to find an American official who says he or she was briefed by Mr. Prince, and I have asked,' Abrams told a press briefing. 'So, I don’t know if he briefed an American official, and if so, who it was.”

Prince has been accused of acting as a back channel on behalf of Trump before. In 2017, he met with an official close to Russian President 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 ahead of time with the knowledge of former White House aide Stephen Bannon.

Prince soared to notoriety after Blackwater employees in 2007 shot and killed Iraqi civilians in Baghdad’s Nisour Square during the Iraq war. After the scandal the company’s name was changed and Prince sold his shares to a private equity fund. Today he heads a private equity fund focused on investments in frontier emerging markets