60,000 people, including the deposed Ali Nasir, fled to the YAR. Ali Salim al-Beidh, an ally of Ismail who had succeeded in escaping the attack on pro-Ismail members of the Politburo, then became General Secretary of the Yemeni Socialist Party. Reforms and attempts for unification Against the background of the perestroika in the USSR, the main backer of the PDRY, political reforms were started in the late 1980s. Political prisoners were released, political parties were formed and the system of justice was reckoned to be more equitable than in the North. In May 1988, the YAR and PDRY governments came to an understanding that considerably reduced tensions including agreement to renew discussions concerning unification, to establish a joint oil exploration area along their undefined border, to demilitarise the border, and to allow Yemenis unrestricted border passage on the basis of only a national identification card. In November 1989, after returning from the Soviet–Afghan War, Osama bin Laden offered to send the newly formed al-Qaeda to overthrow the South Yemeni government on behalf of Saudi Arabia, but Prince Turki bin Faisal found the plan reckless and declined. In 1990, the parties reached a full agreement on joint governing of Yemen, and the countries were effectively merged as Yemen. Demographics South Yemen's ethnic groups were, as of 2000, ethnic Yemeni Arabs (92.8%), Somalis (3.7%), Afro-Arab (1.1%), Indians and Pakistanis (1%), and other (1.4%). Politics and social life South Yemen developed as a Marxist-Leninist, mostly secular society ruled first by the National Liberation Front, which later morphed into the ruling Yemeni Socialist Party. Foreign relations The only avowedly Marxist-Leninist nation in the Middle East, South Yemen received significant foreign aid and other assistance from the USSR and East Germany, which stationed several hundred officers of the Stasi in the country to train the nation's secret police and establish another arms trafficking route to Palestine. The East Germans did not leave until 1990, when the Yemeni government declined to pay their salaries which had been terminated with the dissolution of the Stasi during German reunification. Relations between South Yemen and several of nearby states were poor. Saudi Arabia only established diplomatic relations in 1976, initially hosting pro-British exiles and supporting armed clashes in the border regions of South Yemen. Relations with Oman declined through the 1970s as the South Yemen government supported the insurgent Marxist Popular Front for the Liberation of Oman. Relations with