The Pentagon is prepared to fund 175 miles of border wall construction, Pentagon officials said Tuesday, using $3.6 billion in military construction funds that had been designated for 127 projects over the next year.

Officials declined to release a full list of the affected projects until the Pentagon has finished notifying the lawmakers who oversee the districts where they are planned, but said that family housing, barracks or projects that have had contracts awarded or are expected to be awarded in fiscal year 2020 will not be affected.

The goal, according to the Pentagon’s director of operations for the Joint Staff, is to build new or reinforce existing barriers in 11 locations that will help channel migrants to manned, designated ports of entry, eventually reducing the need for troops to be stationed at the border in those areas.

“So anywhere you’ve now stopped the flow coming across, where we’ve committed both detection and monitoring personnel and border police, we no longer have to commit the same number of personnel,” Lt. Gen. Andrew Poppas told reporters.

About 3,000 active duty and 2,000 National Guard troops are currently deployed to the southwestern border helping the Homeland Security Department with surveillance, detention of migrants and processing asylum requests.

Deployments began late last year after an April 2018 order from President Trump for DoD to assist DHS in its border protection efforts. In February, DoD began a review to determine whether military construction funds should be allocated to support troops deployed to the border.

“In this case, given the uniformly understood border security crisis and humanitarian crisis on the border, we believe in the administration that the use of troops is necessary and appropriate,” Pentagon spokesman Jonathan Hoffman told reporters, and thus, funding construction projects that would support their mission is also necessary.

Within an hour of the announcement, Democrats from the House Appropriations Committee released a letter addressed to Defense Secretary Mark Esper.

“As we have previously written, the decision to take funds from critical military construction projects is unjustified and will have lasting impacts on our military,” they wrote, and contrary to the purpose for those funds. “Our working relationship, and inherent trust contained within, has been further degraded and will necessarily result in stricter controls on funding appropriated.”

The letter requested explanations for the move, as well as a description of the funds to be used and a timeline for completion of the new border wall projects.

Though officials said they anticipated a reduction in troops following construction of these barrier projects, they could not give a timeline of when they would be completed or when a drawdown might start.

It could take between 100 and 145 days to begin construction, Pentagon comptroller Elaine McCusker said. Poppas added that the department was looking at construction at least through FY2020.

“It is replacing vehicular wall in some places. It is adding an additional, secondary wall ― or barrier is the more accurate description ― in other places,” Kenneth Rapuano, the assistant defense secretary for homeland defense and global security, said.

The funding comes from $1.8 billion each in funds designated for domestic and overseas projects, McCusker said. The 127 projects targeted are not canceled, she added, and are not necessarily going to be put on hold.

“The way we’re describing it is, really, deferred,” McCusker said. “If Congress were to back-fill the projects in our request, none of those would be delayed.”

However, they are effectively de-funded unless lawmakers appropriate enough in the 2020 budget to cover both the existing projects and the 11 new border barrier segments.

A complete list of the deferred projects is expected for release on Wednesday, Hoffman told reporters.

The $3.6 billion would add to the existing $2.5 billion the Pentagon has allocated for border projects this year.