An Afghan official says a military offensive has been launched against the Islamic State group in the country's far eastern region, AP reported. Dawlat Waziri, spokesman for the Defense Ministry, said on Tuesday that the offensive began over the weekend in Nangarhar province, bordering Pakistan. It started hours after an IS suicide bomber killed at least 80 people who were taking part in a peaceful demonstration in Kabul on Saturday. Waziri says President Ashraf Ghani gave the orders for the offensive. He says it will consist of airstrikes, ground attacks and clearing operations. A U.S. military spokesman, Brig. Gen. Charles Cleveland, says American forces have also been involved, conducting "multiple counter-terrorism strikes."