President Donald Trump fired back Thursday at House Speaker Nancy Pelosi’s (D-Calif.) request that he delay the State of the Union address until the government shutdown is resolved.

Instead of responding directly to her request that the event be delayed because of security funding concerns, Trump wrote in an apparent retaliation that he had canceled her upcoming delegation trip to Brussels, Egypt and Afghanistan (though Pelosi’s team later said there was no scheduled stop in Egypt).

WH fires back on Speaker Nancy Pelosi's letter over State of the Union. pic.twitter.com/UF1Xsv6y4L — Sam Levine (@srl) January 17, 2019

“Obviously if you would like to make your journey by flying commercial, that would certainly be your prerogative,” the president wrote. The suggestion comes despite the fact that the Air Force budget has not been affected by the 27-day shutdown.

CBS and Fox News both reported that Trump’s letter canceling her trip was issued about an hour before Pelosi was set to depart.

As noted by Politico’s Capitol Hill bureau chief, John Bresnahan, Trump’s public letter exposed a trip that had been a “closely held secret due to security concerns” for Pelosi.

Pelosi's trip to Afghanistan had been a closely held secret due to security concerns, of course. Very few people knew she was heading there. @SteveScalise mentioned Pelosi was headed to Brussels in his presser this morning, which angered Dems. — John Bresnahan (@BresPolitico) January 17, 2019

In a response to Trump, Pelosi’s deputy chief of staff, Drew Hammill, debased the president’s claim that the trip was a mere “public relations event.”

“In Brussels, the delegation was scheduled to meet with top NATO commanders, U.S. military leaders and key allies–to affirm the United States’ ironclad commitment to the NATO alliance,” he tweeted. In Afghanistan, he added, she intended to “obtain critical national security & intelligence briefings from those on the front lines” and thank them for their service.

The speaker, who by tradition invites the president to give the annual address to a joint session of Congress, had asked Trump in a letter Wednesday to reschedule the planned Jan. 29 appearance unless the shutdown ends.

She cited security concerns caused by the shutdown, which has forced the U.S. Secret Service and the Department of Homeland Security to furlough some workers and require others to work without pay.

Today, I wrote to @realDonaldTrump recommending that we delay the State of the Union until after government re-opens, as the @SecretService, the lead federal agency for #SOTU security, faces its 26th day without funding. https://t.co/K2oL8WGvqo pic.twitter.com/g3fIlxDbbK — Nancy Pelosi (@SpeakerPelosi) January 16, 2019

DHS considers the State of the Union to be a “national special security event” requiring “some of the most complex and logistically complicated protective operations undertaken by the Secret Service, often requiring anywhere from 3 to 18 months of planning.”

Sen. Lindsey Graham (R-S.C.) joined in on the kerfuffle Thursday, too. Though he said in a statement that Pelosi’s request was “very irresponsible and blatantly political,” he condemned Trump canceling her trip as “also inappropriate.”

This story has been updated with more context and comments from Hammill and Graham.