His remarks came after it was announced that U.S. President Barack Obama approved airstrikes to drop humanitarian aid and disable IS in Iraq.
"President Obama has acted expeditiously and appropriately in authorizing targeted military action and providing significant humanitarian assistance to the people of Iraq at this very difficult moment when it is vitally needed," he said.
Kerry warned that the situation in Iraq shows how high the stakes are and noted how IS's persecution of minorities could lead to a mass execution.
"ISIL's campaign of terror against the innocent, including Yezedi and Christian minorities, and its grotesque and targeted acts of violence bear all the warning signs and hallmarks of genocide. For anyone who needed a wake-up call, this is it. ISIL is not fighting on behalf of Sunnis. ISIL is not fighting for a stronger Iraq. ISIL is fighting to divide and destroy Iraq -- and ISIL is offering nothing to anyone except chaos, nihilism, and ruthless thuggery."