WASHINGTON - House Speaker Nancy Pelosi, D-Calif., on Wednesday asked President Donald Trump to postpone his State of the Union address — or deliver it in writing — citing security concerns related to the partial federal government shutdown.

The suggestion, which could deny Trump an opportunity to make his case for border-wall funding in prime- time televised address, came as White House officials were urgently lobbying Republican senators against signing a bipartisan letter that would urge an end to a shutdown, now in its 26th day.

In a letter to Trump, Pelosi said the U.S. Secret Service and the Department of Homeland Security, both of which have key responsibilities for planning and implementing security at the scheduled Jan. 29 address in the House chamber, have been "hamstrung" by furloughs.

"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 wrote in the letter.

The White House had no immediate response.

Pelosi later told reporters that the letter was intended as a suggestion and that she was not rescinding the invitation for Trump to speak. "He can make it from the Oval Office if he wants," she added.

House Minority Whip Steve Scalise, R-La., responded on Twitter, suggesting Democrats were trying to deny Trump an opportunity to make his case to the nation.

"#ShutdownNancy shut down the government, and now #SOTU. What are Democrats afraid of Americans hearing? That 17,000+ criminals were caught last year at the border? 90% of heroin in the US comes across the southern border? Illegal border crossings dropped 90%+ in areas w/ a wall?" he wrote.

Meanwhile, senior White House officials were trying to tamp down any signs of division among Republicans as Trump remained unyielding in his demand for $5.7 billion in border wall funding.

In calls to Republican senators placed after news of a draft of a bipartisan letter to Trump became public late Tuesday, Vice President Mike Pence and White House adviser Jared Kushner made clear that the president does not approve of the letter and would not support its call to reopen the government, despite mounting concerns about the political cost of the shutdown for his party, according to a White House aide and three congressional officials who were not authorized to speak about the private discussions.

"The president sees this as a capitulation, and he's not going to walk away," the White House aide said.

Trump's view was echoed by several conservative senators, who expressed skepticism about the moderates' ability to convince Trump and congressional Democratic leaders to reopen the government.

"It's not the time to kick this down the road," Sen. John Cornyn, R-Texas, said of the prospect of opening the government up and keeping talks about border security ongoing. "Apparently this draft has some support, but it's the leadership that'll decide what to do."

Still, the moderates are moving fast to break open the stalled negotiations. The letter is being drafted by senators who took part in a bipartisan meeting earlier this week aimed at finding a way out of the shutdown, now in its 26th day. Details were not final but it would call generally for ending the shutdown and reopening government while negotiations continue on Trump's demands for $5.7 billion for his wall.

Sen. Lamar Alexander, R-Tenn., an ally of Senate Majority Leader Mitch McConnell, R-Ky., said early Wednesday that he intended to sign the letter but the timing and other signers remained in flux, reflecting a desire even among allies of the leadership to break away from Trump's position.

"I see it as a solution," Alexander said of the letter.

Sen. Lisa Murkowski, R-Alaska, who has been urging Trump to reopen the government, said, "We just have to demonstrate that there's more than a couple people that want to do this."

Murkowski added, "We've got to get the president to support it. without that, we're still stumbling along."

Senate Minority Leader Charles Schumer, D-N.Y., is being regularly briefed on the bipartisan group's activities and the count of senators on the letter, aides and lawmakers said, and has encouraged the group to pressure McConnell to act.

The new effort among some senators comes as the White House invited a group of House Democrats and moderate House Republicans to meet with Trump on the shutdown for the second day in a row, this time members of the bipartisan "Problem Solvers" caucus.

White House officials described Wednesday's meeting with the House group as an attempt to contain the frustrations of moderates in both chambers and reiterate how the administration sees what's happening at the border as a crisis that necessitates a wall.

Trump lashed out Wednesday on Twitter at Democrats as "a Party of open borders and crime" and pointed to a surge in construction of border walls by other countries as the standoff continued.

"It is becoming more and more obvious that the Radical Democrats are a Party of open borders and crime," Trump said in one tweet. "They want nothing to do with the major Humanitarian Crisis on our Southern Border."

He added "#2020!" - an apparent reference to a previous contention that Democrats are trying to prevent him from fulfilling a marquee campaign promise in an effort to hurt his reelection prospects.

On Tuesday, a different group of Democrats refused Trump's invitation, as House Democrats sought to maintain unity in rejecting Trump's demands to fund a wall he long claimed Mexico would pay for.

The Washington Post’s Mike DeBonis contributed to this report.