"I have determined that 11 military construction projects are necessary along the international border with Mexico, with an estimated cost of $3.6 billion… to support the use of armed forces in connection with the national emergency," Esper said in a letter that was publicly released on Tuesday. "I have authorized and directed the Acting Secretary of the Army to undertake these 11 projects."
The barriers, he added, are meant to deter illegal entry, channel migrants to ports of entry and will help Defence Department personnel more efficiently support homeland security efforts.
Later on Tuesday, US House Speaker Nancy Pelosi criticized Trump’s decision to divert military funding without congressional approval to build the border wall.
"The House will continue to fight this unacceptable and deeply dangerous decision in the Courts, in the Congress and in the court of public opinion," Pelosi said in a statement.