Stewart, a former U.S. Air Force major who has been briefed on the intelligence findings, said The Post was relying on Democratic Capitol Hill staffers who selectively provided information.
"I've talked with those reporters over the weekend," Stewart said, "and I told them, 'You're going to have to walk back that story because we're going to seek to declassify this information.' "
Stewart visited Moscow in August and upon his return said there was no question the Russian government was "trying to meddle in nearly everything we do," calling the cyberattacks "astounding."
But he stands by his position that the intrusion wasn't aimed at helping one candidate over another; he says the efforts were aimed at undermining confidence in the election.
Trump's transition team blasted the reports of CIA findings of a Russian-led intervention to help his campaign.
"These are the same people that said Saddam Hussein had weapons of mass destruction," the transition said in a statement Friday. "The election ended a long time ago in one of the biggest Electoral College victories in history. It's now time to move on and 'Make America Great Again.' "
Trump's victory was, in fact, not one of the biggest Electoral College victories in history. Barack Obama, for example, had larger Electoral College victories in 2008 and 2012.
Despite little agreement between Republicans and Democrats about the intelligence findings, members of Congress from both parties have called for an investigation into the Russian efforts.
Over the weekend, incoming Senate Minority Leader Chuck Schumer, D-N.Y., joined Sens. Lindsay Graham, R-S.C., John McCain, R-Ariz., and Jack Reed, D-R.I., to call for a probe.
Senate Majority Leader Mitch McConnell, R-Ky., on Monday condemned any foreign interference and said the Senate Intelligence Committee would investigate.
"The Russians are not our friends," McConnell said.
Rep. Rob Bishop, a Utah Republican who says he'd only got secondhand information on the election meddling, dismissed the idea that Russia was trying to help Trump, saying that is a conclusion he does not believe was borne out in findings by intelligence agencies.
"Historically, foreign countries have tried to involve themselves in American elections and even try to influence the outcomes since 1800, when France wanted to help out [Thomas] Jefferson when he was running against [John] Adams," Bishop said. "So a foreign country trying to involve themselves in an election is certainly historically not new and it's not a surprise."
Bishop added that if the Russians, either as a government or individuals, tried to hack the election, it is "to me offensive because any kind of hacking is offensive."