The National Guard will continue its support of Customs and Border Protection along the nation’s southwest border beyond December but its role will be expand beyond providing ground support to include of aerial support, giving the Border Patrol additional surveillance capabilities from the sky, the Defense and Homeland Security Departments said recently.

The current deployment of 1,200 guard troops to the border began in July 2010 and is slated to end this month but under the new plan the National Guard will begin withdrawing some of its troops beginning in January and eventually get down to 300 support personnel in March, officials from the two departments briefed reporters. The National Guard was sent to the southwest border to help staunch the flow of illegal migration and drug smuggling into the United States.

The new Guard mission runs through 2012.

Currently the vast majority of the Guard troops provide entry identification team (EIT) support to the Border Patrol at fixed locations while a small number, about 100, provide criminal investigative support in various sector offices. The EITs will phase out over the next few months while the criminal investigative support will continue.

But now the National Guard’s mission on the border will expand with use helicopters for surveillance and detection missions, providing surveillance coverage well beyond what the EITs can offer from their fixed locations. Moreover, the helicopter assets, both OH-58 Kiowas and UH-72 Lakotas equipped with infrared and advanced sensors, will be able to fly over an area where detection has occurred and provide more visibility, then direct Border Patrol response teams to the location.

“We’re going from boots on the ground to boots in the air,” said Paul Stockton, assistant secretary of Defense for Homeland Defense.

Rick “Ozzie” Nelson, a homeland security analyst with the Center for Strategic and International Studies, said that the reduction of National Guard troops on the border is a “step in the right direction” as is the shifting nature of their mission.

Border security is a law enforcement mission “but if you feel we have to bolster the capabilities of DHS and CBP in order to help them with their mission, the let’s give them niche capabilities,” Nelson said. “Let the law enforcement authorities deal with the immigration issue and use DoD to provide more of a support function, in this case with aviation [assets] and intelligence analysis.”

The exact numbers of aircraft and where they will deploy is still being analyzed. The mission could evolve to include air mobility support to the Border Patrol, allowing for a faster response to events along the border. If so, National Guard UH-60 Black Hawk helicopters may be deployed.

The officials said recently that the use of additional air assets will be based on CBP’s evaluation of its requirements.

In addition to improved surveillance, detection and response capabilities, DHS and DoD said that the new aerial assets will be a deterrent to individuals attempting to cross the border illegally.

CBP already has its own air assets that it uses along the nation’s northern and southern borders, including a mix of fixed- and rotary-wing aircraft as well as the Predator B Unmanned Aircraft System.

When the National Guard deployed troops to the southwest border in 2010, CBP needed the additional ground-based manpower because it was still in the process of expanding the size of the Border Patrol to a record 21,444 agents. That expansion is done and so CBP felt it needed additional aerial surveillance capabilities to better perform its mission.

“We require aerial platforms to provide us with ISR capabilities,” said David Aguilar, assistant commissioner for CBP, referring to intelligence, surveillance and reconnaissance.

The officials said the air asset deployment will cost about $60 million in 2012.