The US-Mexico border fence on the beach at International Friendship Park in Imperial Beach, California (Picture: PA).
US Defence Secretary Mark Esper has approved the use of $3.6 billion (£2.97 billion) in funding from military construction projects to build 175 miles of President Donald Trump's wall along the Mexican border.
Pentagon officials would not say which 127 projects would be affected, but said details would be available on Wednesday after members of Congress were notified.
The officials said half the money would come from military projects in the US, the rest from work in other countries.
Politicians refused earlier this year to approve nearly $6 billion (£4.95 billion) for the wall, but must now decide if they will refund the projects that are being used to provide the money.
Pentagon financial controller Elaine McCusker said the now-unfunded schemes were not being cancelled, with officials instead saying they were being "deferred".
The Defence Department, however, has no guarantee from Congress that any of the money will be replaced.
A number of politicians made it clear during a debate earlier this year that they would not fall for budget trickery and sleight of hand to build the wall.
Senate Democratic Leader Chuck Schumer said: "It is a slap in the face to the members of the Armed Forces who serve our country that President Trump is willing to cannibalise already-allocated military funding to boost his own ego and for a wall he promised Mexico would pay to build."
He added the funding shift would affect the US Military Academy at West Point.
The Pentagon reviewed the list of military projects and said none providing housing or critical infrastructure for troops would be affected.
Defence officials also said they would focus on projects set to begin in 2020 and beyond, with the hope that the money could eventually be restored by Congress.