Army Gen. Lloyd Austin, who leads Central Command, said Islamic State fighters have made Kobani their “main effort” in a move to expand the territory they hold in Syria and Iraq. Austin said attacks by the militants on Kobani have given the U.S.-led air war opportunities to blast the terror group — also known as ISIL or ISIS.

In his first remarks on the air campaign that began in August in Iraq, Austin said progress is being made and called for “strategic patience.” The U.S.-led effort is designed to allow security forces to secure Iraq’s borders, then retrain, re-equip and retake ground lost to Islamic State fighters, he said.

In and around Kobani, Islamic State fighters continue to mass. The bombing campaign has changed the way they communicate and fight, Austin said. Airstrikes have destroyed Humvees, tanks and communication gear. Islamic State fighters are “afraid to talk on their networks” and no longer travel in large convoys, he said.