NAIROBI, Kenya — Erik Prince, the former head of the security contractor Blackwater Worldwide and a prominent supporter of former President Donald J. Trump, violated a United Nations arms embargo on Libya by sending weapons to a militia commander who was attempting to overthrow the internationally backed government, according to U.N. investigators.
A confidential U.N. report obtained by The New York Times and delivered by investigators to the Security Council on Thursday reveals how Mr. Prince deployed a force of foreign mercenaries, armed with attack aircraft, gunboats and cyberwarfare capabilities, to eastern Libya at the height of a major battle in 2019.
As part of the operation, which the report said cost $80 million, the mercenaries also planned to form a hit squad that could track down and kill selected Libyan commanders.
Mr. Prince, a former Navy SEAL and the brother of Betsy DeVos, Mr. Trump’s education secretary, became a symbol of the excesses of privatized American military force when his Blackwater contractors killed 17 Iraqi civilians in 2007.
In the past decade he has relaunched himself as an executive who strikes deals — sometimes for minerals, other times involving military force — in war-addled but resource-rich countries, mostly in Africa.
During the Trump administration, Mr. Prince was a generous donor and a staunch ally of the president, often in league with figures like Steve Bannon and Roger Stone as they sought to undermine Mr. Trump’s critics. And Mr. Prince came under scrutiny from the Trump-Russia inquiry over his meeting with a Russian banker in 2017.
Mr. Prince refused to cooperate with the U.N. inquiry; his lawyer did not respond to questions about the report. Last year the lawyer, Matthew L. Schwartz, told the Times that Mr. Prince “had nothing whatsoever” to do with military operations in Libya.
The report raises the question of whether Mr. Prince played on his ties to the Trump administration to pull off the Libya operation.
It describes how a friend and former partner of Mr. Prince traveled to Jordan to buy surplus, American-made Cobra helicopters from the Jordanian military — a sale that ordinarily would require American government permission, according to military experts. The friend, assured officials in Jordan that he had “clearances from everywhere” and his team’s work had been approved “at the highest level,” the report found.
But the Jordanians, unimpressed by those claims, stopped the sale, forcing the mercenaries to source new aircraft from South Africa.
A Western official, speaking to the Times on the condition of anonymity because he was not permitted to discuss confidential work, said the investigators had also obtained phone records showing that Mr. Prince’s friend and former partner made several calls to the main White House switchboard in late July 2019, after the mercenary operation ran into trouble.
The accusation that Mr. Prince violated the U.N.’s arms embargo on Libya exposes him to possible U.N. sanctions, including a travel ban and a freeze on his bank accounts and other assets — though such an outcome is uncertain.
Mr. Prince is not the only one to have been accused of violating the decade-old arms embargo on Libya. Rampant meddling by regional and global powers has fueled years of fighting, drawing mercenaries and other profiteers seeking riches from a war that has brought only death and misery to a great many Libyans.
The sheer breadth of evidence in the latest U.N. report — 121 pages of code names, cover stories, offshore bank accounts and secretive weapons transfers spanning eight countries, not to mention a brief appearance by a Hollywood friend of Mr. Prince — provides a glimpse into the secretive world of international mercenaries.
Libya began to fracture a decade ago, when the violent ouster of the country’s longtime dictator, Col. Muammar el-Qaddafi, set in motion a political crisis that splintered the country into armed factions, many eventually supported by foreign powers hoping to shape the destiny of the oil-rich North African nation.
Eastern Libya is now in the hands of Khalifa Hifter, the powerful militia commander whom Mr. Prince agreed to support, according to the report, as the country was wracked by fighting in 2019.
A one-time CIA asset who returned from exile in Virginia after the fall of Mr. Qaddafi in 2011, Mr. Hifter rapidly established himself in the eastern city of Benghazi as an aspiring strongman who was determined to blast his way to power if necessary.
In his late 70s, Mr. Hifter has relied for years on the United Arab Emirates for funding, armed drones and a range of powerful weapons, according to successive United Nations reports. More recently, Mr. Hifter has also received backing from Russia, in the guise of mercenaries with the Kremlin-linked Wagner Group that has become an integral part of his war machine.
In April 2019, Mr. Hifter launched a blistering assault on the capital, Tripoli, but formidable obstacles stood in his way, including newly arrived troops from Turkey supporting the U.N.-backed government. So Mr. Hifter turned to Mr. Prince.
Mark Mazzetti contributed reporting from Washington.