WASHINGTON — U.S. officials say the Pentagon is finalizing plans that would send hundreds of additional active-duty troops to the U.S.-Mexico border for several more months to support the Department of Homeland Security.

The troops would install another 160 miles of concertina wire in Arizona and California.

Details are being worked out, but the plan likely would extend the military's border mission though the end of September.

The mission is separate from President Donald Trump’s campaign to build a border wall but is designed to bolster security.

Officials said Friday the installation of the wire barrier is not expected to take long, so troops doing that would be finished long before September.

There currently are 2,350 active-duty troops assigned to the border mission, which was slated to end Jan. 31.

The officials spoke on the condition of anonymity to discuss details not yet approved.