U.S. Secretary of State Rex Tillerson said Wednesday he holds the Burmese military responsible for a brutal ongoing ethnic cleansing campaign against Rohingya minorities, which has killed thousands and driven a half a million Rohingya into neighboring Bangladesh.

Secretary of State Rex Tillerson: “Well, we’re extraordinarily concerned by what’s happening with the Rohingya in Burma. I’ve been in contact with Aung San Suu Kyi, the leader of the civilian side of the government. As you know, this is a power-sharing government that is—that has emerged in Burma. We really hold the military leadership accountable for what’s happening with the Rohingya area.”

Human Rights Watch and other groups have called on the U.N. Security Council to impose an arms embargo against Burma over the ongoing violence. Israel remains one of the major weapons suppliers to the Burmese military.