The Department of Homeland Security has asked the Defense Department to supply an additional 700 National Guard troops and more helicopters for security efforts on the U.S.-Mexico border, according to a DHS official with knowledge of the request.

U.S. Customs and Border Protection said it wants more personnel to support its office, field, intelligence and air and marine operations, a DHS spokesperson confirmed to the Washington Examiner.

Defense Secretary Jim Mattis will respond to the request and is expected to do so "in the coming days," the DHS official added.

President Trump on April 4 approved up to 4,000 National Guard troops being deployed to the southwest border.

Currently, 750 personnel have been deployed as part of ground units and another 200 are expected to be deployed over the next week in California.

CBP officers announced earlier in the day that the back-up personnel have allowed agents to apprehend an additional 1,600 people attempting to illegally enter the country from Mexico since April 15.

National Guard officials overseeing the border state deployments said troops helping monitor the international boundary have freed up more border agents to physically guard the border. The result has led to a surge in the amount of criminal activity agents have stopped, and the interception of another 451 people who were turned back before illegally entering the U.S.

Troops are providing support from the air, surveillance back-up, and assistance with infrastructure projects like vegetation clearing and road maintenance, not including to the border wall construction. Another task is to specifically free up agents to leave their desks and get back out to the field.

The deployment is funded through the end of fiscal year 2018, September 30. Ronald Vitiello, CBP deputy commissioner, said in April the intent of the mission is for CBP to regain operational control of the border.