Lauer said he asked Lochte about skepticism that his story may have been fabricated but the swimmer balked at that suggestion.
"He strongly denied that, said it's absolutely not the case," Lauer said.
"I wouldn't make up a story like this nor would the others — as a matter of fact we all feel it makes us look bad," Lauer said, quoting Lochte. "We're victims in this and we're happy that we're safe."
State Department spokesman John Kirby said the U.S. government was aware of the situation. "We have seen media reports that two U.S. citizen athletes were detained. We stand ready to provide all appropriate consular assistance," Kirby said in a statement.
The swimmers are subject to questioning and potential charges if police believe they gave false or misleading statements to authorities, which can carry up to six months in jail.
But under Brazil's constitution ratified in 1988, they have the right to remain silent.
Lochte repeated his story of what happened in large part, but a few details changed, Lauer said during NBC Sports coverage of the Olympics Wednesday night.
In an interview with TODAY's Billy Bush on Sunday, just hours after the alleged robbery, Lochte had said the gun was put against his forehead — but said in Wednesday's telephone conversation that the gun was pointed in his general direction but the weapon was cocked, Lauer reported.
Lochte did not repeat part of his story that their taxi was pulled over by the robbers, Lauer said.
Lochte said Wednesday they were at a gas station and got back in the taxi, the taxi driver did not move, and it was then that two robbers with guns and badges approached the car and ordered the swimmers out of the vehicle and onto the ground, Lauer said.
Ostrow, the lawyer, said Lochte gave police a statement as representatives from the U.S. State Department, United States Olympic Committee and the FBI observed. Lochte signed the statement to attest to its truthfulness, Ostrow added.
Police did not ask Lochte for more information, and they did not ask him to remain in Brazil, Ostrow said.
"They never said, 'Stay around,'" Ostrow said. "Otherwise, I would have advised Ryan to stay."
He accused Brazilian authorities of trying to "save face" after allowing the incident to become "a circus."
Lochte said in the telephone interview that he initially didn't want to tell the story of the armed robbery because they were worried they'd broken swim team rules, Lauer said.
Once he realized he hadn't broken any rules by being out drinking because he was over 21, Lochte said he felt it was OK to tell the story, Lauer added.
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