In 2016, he was accused of forcing the resignation of Prime Minister Ahmet Davutoğlu due to his scepticism over the proposed presidential system, resulting in his replacement by close ally Binali Yıldırım. He has also come under fire for constructing Ak Saray, the world's largest palace on Atatürk Forest Farm and Zoo for his own use as President and has been repeatedly accused of breaching the constitutional terms of his office by not maintaining political neutrality. In 2015, amid consistent allegations that he maintained financial links with Islamic State of Iraq and the Levant militants, revelations that the state was supplying arms to militant groups in Syria in the 2014 National Intelligence Organisation lorry scandal led to accusations of high treason.[295][296][297] In July 2015, Turkey became involved in the war against ISIS.