President Trump has been briefed about using disaster-relief money meant to help storm-soaked Puerto Rico and fire-ravaged California to build his border wall, according to a report.

If Trump declares a national emergency, he could dip into a $13.9 billion Army Corps of Engineers fund intended for public works, NBC reported.

Of that money, $2.5 billion is allocated for ongoing recovery from Hurricane Maria in Puerto Rico, and $2.4 billion is set aside to improve infrastructure along the the Yuba River Basin in California.

Defense Department officials discussed the plan with Trump Thursday as he traveled to the southern border.

Trump needs $5.7 billion to build the long-promised wall along the nation’s southern border.

Twenty days ago, parts of the federal government were shut as part of his ongoing feud with Democrats, who are blocking funding for the border wall with Mexico.

Officials told Trump the Army Corps could put up 315 miles of 30-foot, bollard-style barrier in 18 months, according to NBC, which cited sources.

But siphoning off money for disaster relief and mitigation will put American lives at risk, a Congressional staffer told the outlet.

“Hundreds of thousands of people will be at risk if there is a strong or wet winter in these flood areas and the protection projects haven’t been completed,” the staffer said.