A portion of a letter sent to President Donald Trump from House Speaker Nancy Pelosi, Wednesday, Jan. 16, 2019 in Washington. (Photo: AP)

House Speaker Nancy Pelosi has asked President Donald Trump to postpone his State of the Union address to the nation — set for Jan. 29 — until the government reopens.

The White House hasn't immediately responded to a request for comment about Pelosi's request, which she made in a letter to the president.

Pelosi says the partial shutdown is raising concerns about security preparations for the speech. The California Democrat notes that the Secret Service and Department of Homeland Security have been without funding for almost four weeks.

The annual speech is perhaps the president's biggest opportunity to present his agenda directly to the public.

Pelosi writes that "given the security concerns and unless government reopens this week, I suggest that we work together to determine another suitable date after the government has re-opened."

She's also raising the possibility that Trump deliver the message in writing, as presidents once did.

Congress is planning to skip next week's planned recess if the partial government shutdown continues. And there's every indication it will drag on.

Neither side is showing signs of backing down.

President Donald Trump has told supporters in a conference call that the shutdown will continue, in his words, "for a long time" if it has to.

And Trump contends that people are impressed at how well the government is working.

Democrats remain opposed to Trump's demand for $5.7 billion to build a wall along the U.S.-Mexico border. They say they'll discuss border security once the government has reopened.

An effort by the White House to divide House Democrats fizzled when centrist and freshmen Democrats didn't accept a White House invitation to lunch with Trump on Tuesday.