Richard Grenell, the former acting U.S. Director of National Intelligence and former ambassador to Germany, had discussions in Mexico City with Jorge Rodriguez, a close associate of Maduro, the sources said.
There was no immediate comment from the White House or State Department.
President Donald Trump has become increasingly frustrated over the failure of his policy of sanctions and diplomatic pressure to unseat Maduro, U.S. officials have said privately.
Maduro, a socialist whose 2018 re-election was considered a sham by most Western countries, has retained the support of Russia, China, Cuba and Iran. He is also backed by Venezuela’s military.
As Trump seeks re-election on Nov. 3 trailing Democratic rival Joe Biden in opinion polls, he has sought foreign policy achievements that he can tout in the campaign’s final phase. Grenell is also a senior Trump campaign adviser.
The sources gave conflicting views on whether the meeting was worthwhile but all agreed that no deal was struck or even significant progress made toward Maduro’s exit.
One source said Maduro’s representative showed some interest in finding a solution but signaled a desire to await the outcome of the U.S. election.
Another person familiar with the matter said arranging such talks may have sent a message of U.S. desperation that would only prompt Maduro to further entrench himself.
“They do want a solution, but they’re waiting to see who the next president will be,” the first source told Reuters. “It was clear that they were trying to buy time.”
Grenell’s meeting, first reported by Bloomberg News, followed earlier secret contacts between the Trump administration and Venezuelan officials, one of the sources said, without elaborating.
The meeting in Mexico’s capital was not coordinated with the U.S. State Department, where Elliott Abrams serves as envoy on Venezuela and Iran, another of the sources said.
It was not known how the talks were arranged, but the source said no further meeting was scheduled.
Grenell, the special envoy for Serbia and Kosovo peace negotiations, was also involved in reaching a recent agreement between Serbia and Kosovo to work on improving economic ties.
But he is not known to have played a role before in Venezuela policy or other major Latin American issues.
Reporting by Andrea Shalal, Steve Holland and Matt Spetalnick; editing by Grant McCool