US Marines put up barbed wire at the US-Mexico border in California (Picture: US Department of Defense).
Another 3,750 more troops are to be sent to the US-Mexico border to help put up another 150 miles of barbed wire, the Pentagon has confirmed.
It will see the total number of active-duty troops on the border rise to 4,350.
The new soldiers will also provide support for the Customs and Border Protection.
The announcement comes after Acting Defence Secretary Pat Shanahan had earlier confirmed that several thousand more troops would be sent to mainly to install additional wire barriers and provide a large new system of mobile surveillance and monitoring of the border area.
The Pentagon said the mobile surveillance mission would last until 30 September.
Critics have derided the announcement as a political ploy by the White House as President Donald Trump seeks billions to build a border wall.
Members of Congress have question whether the border mission is distracting troops from their main work of fighting extremists abroad and training for combat.
Active-duty troops were first sent to the border on 30 October, with a mission that was expected to last until 15 December. However, it has since been extended twice.
Vice Admiral Mike Gilday, the director of operations for the Joint Staff, has previously said that he does not believe military readiness has been significantly affected by the border mission.