since ousted President Salah Jadid), the Palestinian fighters crossed the border into Lebanon to join PLO forces in that country, where they set up their new headquarters. Headquarters in Lebanon Official recognition Because of Lebanon's weak central government, the PLO was able to operate virtually as an independent state. During this time in the 1970s, numerous leftist PLO groups took up arms against Israel, carrying out attacks against civilians as well as military targets within Israel and outside of it. Two major incidents occurred in 1972. The Fatah subgroup Black September Organization hijacked Sabena Flight 572 en route to Vienna and forced it to land at the Ben Gurion International Airport in Israel. The PFLP and the Japanese Red Army carried out a shooting rampage at the same airport, killing twenty-four civilians. Israel later claimed that the assassination of PFLP spokesman Ghassan Kanafani was a response to the PFLP's involvement in masterminding the latter attack. Two days later, various PLO factions retaliated by bombing a bus station, killing eleven civilians. At the Munich Olympic Games, Black September kidnapped and killed eleven Israeli athletes. A number of sources, including Mohammed Oudeh (Abu Daoud), one of the masterminds of the Munich massacre, and Benny Morris, a prominent Israeli historian, have stated that Black September was an armed branch of Fatah used for paramilitary operations. According to Abu Daoud's 1999 book, "Arafat was briefed on plans for the Munich hostage-taking." The killings were internationally condemned. In 1973–74, Arafat closed Black September down, ordering the PLO to withdraw from acts of violence outside Israel, the West Bank and Gaza Strip. In 1974, the PNC approved the Ten Point Program (drawn up by Arafat and his advisers), and proposed a compromise with the Israelis. It called for a Palestinian national authority over every part of "liberated" Palestinian territory, which refers to areas captured by Arab forces in the 1948 Arab–Israeli War (present-day West Bank, East Jerusalem and Gaza Strip). This caused discontent among several of the PLO factions; the PFLP, DFLP and other parties formed a breakaway organization, the Rejectionist Front. Israel and the US have alleged also that Arafat was involved in the 1973 Khartoum diplomatic assassinations, in which five diplomats and five others were killed. A 1973 United States Department of State document, declassified in 2006, concluded "The Khartoum operation was planned and carried out with the full knowledge and personal approval of