In a speech to hundreds of his supporters in southern Beirut today, Sheikh Hassan Nasrallah says the CIA and Israel's Mossad are behind the extremist group, which serves their interests.
He claims Israel is the only country which has not been affected and does not consider the group a threat.
The Iranian-backed Shiite Hezbollah group, which has sent thousands of its fighters to Syria to help shore up President Bashar Assad's forces, has positioned itself as a vanguard against Sunni extremists such as the Islamic State group.