A White House spokesman described the report as "false"
US President Donald Trump may mobilise up to 100,000 national guard troops to round up illegal immigrants, the Associated Press has reported.
AP says it has obtained a draft memo that outlines the proposals to target unauthorised citizens in 11 US states.
However, a White House spokesman described the report as "false", but did not deny existence of the memo.
According to the AP, the 11-page memo calls for the unprecedented militarisation of immigration enforcement.
Millions of those who would be affected live nowhere near the Mexico border, according to the document.
The enforcement would stretch as far north as Portland, Oregon, and as far east as New Orleans, Louisiana the memo suggests.
New-York based reporter, Hannah Thomas-Peter, said the White House had stopped short of denying that the memo existed.
"This will send shockwaves through those communities.
"Whether or not it is under active consideration is almost beside the point for America's estimated 11 million undocumented immigrants.
"I have spent the last couple of days filming with members of these communities living in and around New York and they are already terrified.
"The other point is that Donald Trump has less than 24 hours ago declared that these illegal leaks, as he called them, would end.
"But this is another very serious leak which had taken hold of the news agenda and will now make huge headlines.
"It is adding fuel to this argument that actually Donald Trump's biggest enemy at the moment is not the media but his own government."
If the proposal is implemented, governors in the affected states would have final say on whether troops participated, said the AP.
White House press secretary Sean Spicer said: "That is 100% not true. It is false. It is irresponsible to be saying this.
"There is no effort at all to round up, to utilize the National Guard to round up illegal immigrants.
"I wish you guys had asked before you tweeted," he added.
This is not true. DHS also confirms it is 100% false https://t.co/MFIJci7XaU— Sean Spicer (@PressSec) February 17, 2017
An AP reporter said the agency had asked multiple times before publication.
Mr Spicer could not categorically state that this was never a subject of discussion somewhere in the administration.
"I don't know what could potentially be out there, but I know that there is no effort to do what is potentially suggested.
"It is not a White House document."