The United Nations Security Council has taken aim at Lebanese militant group Hezbollah and its role in Syria, issuing a warning late on Friday for all Lebanese parties to dissociate themselves from any external conflicts.

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.