(CNN) Speaker Nancy Pelosi canceled a planned trip to visit troops in Afghanistan Friday, after -- her office alleged in a statement -- the White House leaked the details of the congressional delegation's commercial plane travel.

"In the middle of the night, the State Department's Diplomatic Security Service provided an updated threat assessment detailing that the President announcing this sensitive travel had significantly increased the danger to the delegation and to the troops, security, and other officials supporting the trip," Pelosi spokesman Drew Hammill said. "This morning, we learned that the administration had leaked the commercial travel plans as well."

Which, to borrow the parlance of the Internet, is VERY big, if true.

It's one thing for Trump, as he did on Thursday, to rescind the military plane Pelosi and the rest of her colleagues were planning to fly on as a way of exacting revenge on her for asking the President to delay his planned "State of the Union" speech on January 29. To do so publicly -- White House press secretary Sarah Sanders tweeted out the letter Trump sent to Pelosi -- is to raise the stakes. To leak commercial travel plans to make absolutely certain that Pelosi can't go on the trip is a bridge even further.

Now, to be clear, this is an allegation made by Pelosi without corroboration to date. And, the White House denies it. "When the Speaker of the House and about 20 others from Capitol Hill decide to book their own commercial flights to Afghanistan, the world is going to find out," a White House official told CNN's Sarah Westwood and Kevin Liptak . "The idea we would leak anything that would put the safety and security of any American at risk is a flat out lie."

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