US military forces patrolling the country’s southern approaches are under-resourced and overwhelmed by the flow of drugs and contraband coming north, military and Coast Guard leaders said in recent weeks.

Both US Southern Command, which oversees military operations beyond Mexico’s southern border, and the US Coast Guard, have been strained by the scope of their duties and limitations on their budgets.

As a result, their units can confront less than one-third of the drug shipments making their way to the US.

“We continue to have these shortfalls,” Adm. Kurt Tidd, SouthCom chief, told the Senate Committee on Armed Services during testimony last week.