U.S.-led coalition warplanes struck Islamic State’s last stronghold in eastern Syria and hundreds of civilians fled the besieged enclave on Monday as U.S.-backed fighters pressed their campaign to seize it.

Iran’s Foreign Minister Mohammad Javad Zarif who arrived in Lebanon on Sunday met Hassan Nasrallah the leader of the militant group Hezbollah. In recent days, Hezbollah has been pushing the idea of Lebanon officially accepting Iranian military assistance, which Zarif earlier said Iran would be looking forward to.

Islamic State group militants cornered in their last foothold in eastern Syria fought back with suicide car bombs, snipers and booby traps Monday, slowing Kurdish fighters advancing under the cover of U.S.-led coalition airstrikes, Kurdish news agencies and a Syrian war monitor said.