Military cooperation between Israel and Iran had been extensive since the 1960s, under the shah's regime. After a brief rupture of relations when Ayatollah Sayyid Ruhollah Musavi Khomeini came to power in 1979, cooperation resumed. The Israeli minister of defense in 1982 acknowledged the negotiation of an arrangement worth US$28 million, including spare parts for United States-manufactured airplanes and tanks in the early 1980s. The Israeli motivating factor was the belief that it was to Israel's strategic advantage to help Iran in its war against Iraq, an Arab state bitterly hostile to Israel. Although Israel announced an embargo of arms transactions after disclosure of its involvement in the plan to trade arms for the release of United States hostages in Lebanon, a stricter directive had to be issued in November 1987, following reports that weapons of Israeli origin continued to reach the Iranians.