Defense Secretary James Mattis said Monday he’s “shocked” by the decline in US military readiness and placed the blame squarely on Congress.

Mattis scolded lawmakers on Capitol Hill for failing to pass military budgets and for imposing automatic spending cuts known as sequestration that have caused “severe” damage.

“I retired from military service three months after sequestration took effect,” Mattis, a former Marine Corps general who retired in 2013, said. “Four years later, I’ve returned to the department and I have been shocked by what I’ve seen about our readiness to fight.”

Testifying before the House Armed Services Committee, Mattis told members of Congress they’ve caused “harm” by their lack of leadership.

“While nothing can compare to the heartache caused by the loss of our troops during these wars, no enemy in the field has done more to harm the combat readiness of our military than sequestration,” Mattis said. “We have only sustained our ability to meet America’s commitments abroad because our troops have stoically shouldered a much greater burden.”

Mattis is asking Congress to pass President Trump’s 2018 spending request of $639.1 billion, to end sequestration and to allow the military to appropriately plan by passing a budget on time.