US President Donald Trump has postponed House Speaker Nancy Pelosi's trip to Brussels, Egypt and Afghanistan in an apparent response to her suggestion that he reschedule his annual State of Union address.

The president cited the government shutdown, the longest-ever in US history, for postponing Pelosi's foreign trip.

Trump's move came on Thursday a day after the House Speaker urged him to reschedule his annual State of the Union address slated for January 29, citing security concerns triggered by the shutdown that has entered its 27th day.

"Due to the shutdown, I am sorry to inform you that your trip to Brussels, Egypt, and Afghanistan has been postponed. We will reschedule this seven-day excursion when the Shutdown is over," Trump said in a letter to Pelosi, a copy of which was released to the press.

The president also said postponing this "public relations event" was totally appropriate.

The shutdown has rendered over 800,000 federal employees without work, crippling the functioning of several key wings of the government including Security and State department.

“In light of the 800,000 great American workers not receiving pay, I am sure you would agree that,” Trump said.

The shutdown is a result of the bitter political divided over border security issue as the Democrats who now enjoy majority in the House have refused to approve a legislation approving USD 5.7 billion in federal funding to construct a wall across the US-Mexico border.

"I also feel that, during this period, it would be better if you were in Washington negotiating with me and joining the strong border security movement to end the shutdown. Obviously, if you would like to make your journey by flying commercial, that would certainly be your prerogative,” Trump said.

He said, “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!”

Trump’s letter to Pelosi came soon after the House Speaker told reporters at the US Capitol that the president has been mum on for more than 24 hours on the issue of rescheduling his annual State of the Union address.

“We haven't heard. It was a very silent more than 24 hours, to your question that you ask me every time I step out of the office, have you heard? No, we haven't heard yet.” Pelosi said taking a dig at the president.

In her letter, Pelosi had also told Trump Wednesday that the US Secret Service was designated as the lead federal agency responsible for coordinating, planning, exercising and implementing security for National Special Security Events by Public Law 106-544, December 19, 2000.

"However, both the US Secret Service and the Department of Homeland Security have not been funded for 26 days now - with critical departments hamstrung by furloughs," she said.

"Sadly, given the security concerns and unless government re-opens this week, I suggest that we work together to determine another suitable date after government has re-opened for this address or for you to consider delivering your State of the Union address in writing to the Congress on January 29th," Pelosi said.

In a tweet Wednesday, Homeland Security Secretary Kirstjen Nielsen, however, said the Department of Homeland Security and the secret services were "fully prepared to "support and secure" the State of the Union.

"The Department of Homeland Security and the US Secret Service are fully prepared to support and secure the State of the Union. We thank the Service for their mission focus and dedication and for all they do each day to secure our homeland," Nielsen had said on Twitter.

President Trump insists that building a wall is the only solution to protect the nation from a large flow of illegal immigrants and drug smuggling. The Democrats are opposed to any such funding. After Trump walked out of a meeting at the White House last week, Democrats have refused to come to the negotiation table.

PTI