US-led forces conducted six air strikes against Islamic State militants and one against the al-Qaida-affiliated Khorasan Group in Syria since Monday and 24 air strikes in Iraq during the same period, US Central Command said.The strikes against Islamic State in Iraq were concentrated on the oil-producing north and included 13 near Kirkuk and seven near Mosul, Centcom said in a statement.In Syria, five air strikes hit near Kobani and one in northwestern Haram destroyed a storage facility linked to the Khorasan Group, it said.