President Donald Trump on Thursday cancelled the official trip abroad by House Speaker Nancy Pelosi due, he said, to the partial government shutdown.

Trump communicated his decision to Pelosi in a letter, which arrived just one day after Pelosi had requested in a missive of her own that the president postpone his traditional State of the Union address to Congress, scheduled for Jan. 29, until after the government fully reopens.

"Due to the Shutdown, I am sorry to inform you that your trip to Brussels, Egypt, and Afghanistan has been postponed," Trump wrote Pelosi on Thursday. "We will reschedule this seven-day excursion when the Shutdown is over."

"Obviously, if you would like to make your journey by flying commercial, that would certainly be your prerogative," Trump wrote.

Pelosi had been scheduled to use a military aircraft for her official trip abroad, as is usual for this kind of travel.

However, as president, Trump has the authority to order the Defense Department not to use its funds to facilitate the trips of members of Congress.

Trump made public his letter just 45 minutes before Pelosi's plane was scheduled to take off at 3 pm, according to Fox News.

In a statement on Twitter, Drew Hammill, one of Pelosi's spokespeople, said that the aim of the trip was to "express appreciation & thanks to our men & women in uniform for their service & dedication, & to obtain critical national security & intelligence briefings from those on the front lines."

Hammill also recalled that Trump had paid a surprise visit to US troops in Iraq on Dec. 26, just after the start of the shutdown.

In addition, Hammill corrected the itinerary that Trump had mentioned and said that Pelosi was not scheduled to travel to Egypt and that she was only going to make a short stop in Brussels to meet with commanders of NATO, the trans-Atlantic military alliance that the US president has harshly and repeatedly criticized.

Since Dec. 22, about 25 percent of the federal government has been shut down because of Trump's demand that $5.7 billion be included in the US budget bill to start construction of his much-touted wall along the US-Mexico border, a proposal that has been rejected out of hand by the new Democratic majority in the lower house of Congress as being contrary to American values, wasteful and inefficient at resolving a range of border issues.

In his letter, Trump notes that 800,000 federal workers are not receiving paychecks because of the lack of approved funding and, in light of that situation, he tells Pelosi: "In light of (that) ... I am sure you would agree that postponing this public relations event is totally appropriate."

"I also feel that, during this period," Trump wrote, "it would be better if you were in Washington negotiating with me and joining the Strong Border Security movement to end the Shutdown."

The president signs off to Pelosi by saying that "I look forward to seeing you soon and even more forward to watching our open and dangerous Southern Border finally receive the attention, funding, and security it so desperately deserves!"