The Pentagon has authorized a payment of $1 billion to begin building a portion of President Trump’s proposed southern border wall, according to US officials.

Secretary of Defense Patrick Shanahan notified Congress on Monday night about the shift in military funds and asked that the US Army Corps of Engineers “begin planning and executing” the construction of a 57-mile strip of fencing along the Yuma and El Paso sections of the US-Mexico border.

The Department of Homeland Security requested the 18-foot-high wall to be put into place not long after Trump declared a state of emergency in the region. DHS officials also asked for local roads to be improved and better lighting to be installed.

According to the Pentagon, the $1 billion that Shanahan authorized for the wall construction “will be used to support DHS’s request.”

The Trump administration plans to spend another $1.5 billion on future projects.

Illinois Sen. Dick Durbin — the top Democrat on the Pentagon’s appropriations panel — told the Associated Press earlier this month that the DOD funding would be “coming out of military pay and pensions.”

“That’s the plan,” he said. “$1 billion.”

With Post wires