Chairman of the Joint Chiefs of Staff Gen. Dan Caine told U.S. senators on Thursday that Russia has been assisting Iran’s war effort, confirming involvement during testimony before the Senate Armed Services Committee.

Speaking at a hearing on the ongoing two-month-old U.S. war against Iran, Caine said Russia is taking active steps that affect U.S. military objectives in the region.

While declining to provide classified details in a public setting, he said, “There’s definitely some action there.”