President Donald Trump said Tuesday that he’s directing the U.S. military to secure the U.S.-Mexico border in lieu, for now, of a border wall.

“We’re going to be doing things militarily until we can have a wall and proper security.” Trump said.

Trump’s comments came as he sat near Secretary of Defense Jim Mattis, who was reportedly at the White House for discussions around immigration.

A defense official who spoke on the condition of anonymity had no immediate details as to how many troops would be used, or what authorities they would have, but said the presence could be similar to the 2006-2008 patrols U.S. military personnel conducted under Operation Jump Start.

In that operation, President George W. Bush called for up to 6,000 National Guard members to secure parts of the border. Eventually 29,000 military personnel from all over the country were involved in the mission, which had a projected cost of around $1.2 billion in then-year dollars.

In 2012, President Barack Obama deployed Army forces from Ft. Bliss to the Tucson, Arizona and El Paso, Texas areas for Operation Nimbus, a joint operation between U.S. Northern Command and Customs and Border Patrol.

Per an Army press release at the time, military forces conducted “day and night reconnaissance missions using the Long Range Advanced Scout Surveillance System to detect, recognize, identify and geo-locate possible incursions, which they would then report to Border Patrol agents. Avenger Soldiers, using the Forward Looking Infrared system, and Soldiers monitoring Sentinel radar, also augmented border air incursion detection efforts.”

This story is developing and will be updated.

US President Donald Trump inspects border wall prototypes in San Diego, California on March 13, 2018. On Tuesday Trump said the U.S. military would be used to secure the border until a wall can be funded and built. Donald Trump — making his first trip to California as president — warned there would be “bedlam” without the controversial wall he wants to build on the border with Mexico, as he inspected several prototype barriers.