Defense Secretary Jim Mattis says senior military leaders are taking a close look at whether strict budget constraints have led to a recent rash of deadly training accidents and crashes across the armed forces.

Since mid-July, nearly 100 U.S. service members have been killed or injured in close to a dozen mishaps, among them ship collisions, military aircraft crashes and a Marine amphibious vehicle that ran over a gas line.

Mattis says he's not convinced that tight budgets have contributed to accidents but that's being looked at. He says the military can't keep doing more with less.

Mattis says it's important to look at all circumstances to see if there are any broader cultural or training problems. He denies that military commanders are afraid to suggest their troops aren't ready.