Vaughters, currently a team director at Garmin-Sharp's cycling team, said at the start of Thursday's fifth stage that the report is "completely untrue." Garmin-Sharp's parent company, Slipstream, later supported Vaughters' denial in a statement.
"We can confirm that our Tour team is entirely focused on the Tour and media reports of suspensions are untrue," the company said.
USADA wouldn't confirm the De Telegraaf report but released a statement warning that those named could be subject to "unnecessary scrutiny, threats and intimidation."
"Any attempt to circumvent the proper procedures in order to bully or silence people who may or may not be witnesses cannot be tolerated," the statement said.
Vande Velde and Zabriskie are part of the Garmin team. Leipheimer, who rides for Omega Pharma-QuickStep, said: "I'm just here to ride the Tour de France, and so far I'm still in the hunt for the general classification. I can't say anything."
Hincapie, who rides for BMC, said he just wants to help Cadel Evans keep his Tour title. Hincapie said he hasn't spoken to Armstrong recently.
"I'm sad he is going through this," he said. "He's done so many things for the sport. His accomplishments are incredible."
BMC team manager Jim Ochowicz denied knowledge of the bans.
"We've not received any information from any authority about this issue at all," he said.
Armstrong has always strenuously denied doping and a two-year federal investigation ended in February with no criminal charges against the Texan.
USADA, however, has filed formal charges against Armstrong, accusing him of using performance-enhancing drugs throughout the best years of his career.
The agency notified Armstrong and his former team manager, Johan Bruyneel, plus several of his team associates of the charges in a letter last month.
The charges came after a USADA review panel examined evidence in the case, which now goes to an arbitration panel to decide. If found guilty, Armstrong could be stripped of the Tour titles he won from 1999-2005.
Armstrong's lawyer, Robert Luskin, calls the charges "wrong and baseless."
Bruyneel, who ran the US Postal team when Armstrong won his first six Tour titles, is now Radioshack Nissan manager. He decided to skip the Tour this year to avoid being a distraction for his team and the race.
USA Cycling said last month about the time USADA filed charges against Armstrong that Leipheimer, Hincapie, Vande Velde and Zabriskie asked to be overlooked for the Olympic team for the London Games.
Hincapie said this week that he didn't want to go to the Olympics as he would be away from his family for most of July at the Tour.
Leipheimer declined to say whether his decision to skip the Olympics is related to the USADA investigation.
"Really, no comment," Leipheimer said Thursday. "I did have a broken leg in the year, and I don't know if I was the best choice to go to the Olympics."