A U.S. delegation walked out of the UN General Assembly hall during a speech from Iranian President Mahmoud Ahmadinejad, who said the U.S. government was behind the September 11 terrorist attacks in New York. Addressing the delegates from 192 nations, Ahmadinejad said there were three theories of the tragic events and in line with one of them "some segments within the U.S. government orchestrated the attack to reverse the declining American economy, and its grips on the Middle East, in order to save the Zionist regime." Delegations from other countries, including Britain and France, joined the U.S. delegates and also left the hall in protest. Four airliners were hijacked on September 11, 2001. Two planes crashed into the twin World Trade Center towers in Lower Manhattan. A short time later hijackers flew another plane into the Pentagon while the fourth crashed in rural Pennsylvania. In all, 2,975 were people killed. In May this year, U.S., French and British delegations walked out of the UN General Assembly hall during Ahmadinejad's speech when he accused Western powers of double standards concerning nuclear non-proliferation.