A request from Israel for 1,100 mile (1,770 km) range Pershing II medium range ballistic missiles was rejected by the United States for inclusion as part of a military assistance incentive package offered in 1975 during negotiations over transferring the Sinai from Israeli to Egyptian control as part of a US-brokered peace deal. Jericho II development began in 1977, and by 1986 there were reports of test firings. According to Missilethreat, a project of the George C. Marshall Institute, there is evidence the Jericho II originated as a joint Israeli-Iranian project, cooperation that ended with the loss of friendly relations after the 1979 Islamist revolution overthrew the Shah's rule. There was a series of test launches into the Mediterranean from 1987 to 1992, the longest at around 1,300 km, mostly from the facility at Palmachim, south of Tel Aviv. Jane's reports that a test launch of 1,400 km is believed to have taken place from South Africa's Overberg Test Range in June 1989.