In July 2009, U.S. President Barack Obama arrived in Saudi Arabia and held talks with King Abdullah at the start of a Middle East tour aimed at increasing U.S. engagement with the Islamic world. In October 2010, U.S. officials confirmed a plan to sell $60 billion worth of arms to Saudi Arabia - the most lucrative single arms deal in US history.[21] Relations were hurt over the United States diplomatic cables leak by the whistle-blowing website Wikileaks in December 2010. They suggested that the USA was concerned that Saudi Arabia was the most significant source of funding for Sunni terrorist groups worldwide.