The Iraqi air force has dropped weapons to the self-proclaimed Islamic State in Iraq and Syria (ISIS) by mistake, an Iraqi MP has claimed.Iskandar Witwit, a member of parliament's security committee, told Anadolu Agency on Friday that "Iraq army planes dropped amounts of weapons and ammo to the Iraqi security forces that are besieged by ISIS in Baiji oil refinery, but [the] dropping operation was mistaken ... that enabled ISIS members to seize most of the weapons."Witwit did not specify the date of the alleged incident.ISIS has been attempting recently to seize complete control of Iraq's Baiji oil refinery complex.On Monday, Pentagon spokesman Army Col. Steve Warren had said that Baiji complex had been severely damaged and was barely operational as the facility remains contested between Iraqi forces and ISIS militants.The oil-rich eastern city of Baiji was cleared of ISIS last November but it fell to the militant group early this year.It was then again taken in late April by Iraqi forces in cooperation with a U.S-led coalition.