Democrats have asked President Donald Trump to postpone a speech to Congress, arguing security cannot be guaranteed due to the government shutdown. Speaker of the House Nancy Pelosi said in a letter to Mr Trump that he should deliver the speech in writing instead unless federal agencies reopen.
Mr Trump is due to address Congress for the annual State of the Union speech on 29 January. The US government is partially shut due to a row over border security.
The Republican president is demanding US$ 5.7bn of congressional funding to build a wall on the US-Mexico border, but newly empowered Democrats have refused.
The White House response came from Homeland Security Secretary Kirstjen Nielsen, who tweeted that her department and the US Secret Service are fully prepared to support and secure the State of the Union.
In Wednesday's letter, Mrs Pelosi cited the extraordinary demands presented by the State of the Union speech. She wrote: 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.
Sadly, given the current security concerns and unless government reopens this week, I suggest we work together to determine another suitable date.
Later in the morning, Mrs Pelosi suggested to reporters after a party leadership meeting that Mr Trump could give his speech from the White House Oval Office if he wants”.
The White House did not immediately respond to the House of Representatives speaker's suggestion.
According to the US Nation al Archives, the third US President, Thomas Jefferson, began delivering his State of the Union addresses in writing. The tradition was upheld for more than a century until President Woodrow Wilson spoke in person to a joint session of Congress in 1913.
The political extravaganza is attended by every member of Congress, as well as Supreme Court justices and military top brass.
Meanwhile the shutdown, now on day 27, is inflicting more damage to the US economy than previously predicted, one of Mr Trump's advisers has acknowledged.
The White House Council of Economic Advisers doubled projections of how much growth is being lost each week the standoff endures. Chairman, Kevin Hassett, said that initial estimates of the impact did not fully factor in private companies that have federal government contracts.
Economists say that while the blow to overall growth remains a glancing one so far, it could become a direct hit if the shutdown is not resolved by next month.
Some of the 800,000 federal employees who have been going unpaid since 22 December are in increasingly dire straits. In desperation the Department of Agriculture, the Internal Revenue Service and the Federal Aviation Administration have just recalled more than 50,000 employees, who must work without pay.
According to a Pew Research Center opinion poll, a divide in public support for the wall is continuing to widen. The survey, released on Wednesday, finds that 58% of Americans oppose building any new walls on the US-Mexico border, while 40% support the measure.