Pakistan has enjoyed strong military co-operation with the Iranian military since the 1950s. Iranian leader Mohammad Reza Shah provided free fuel to PAF fighter jets in the Indo-Pakistani War of 1965, allowing Pakistani planes to land at Iranian Air Force bases, refuel, and take off. The military relationship continued even after the Iranian revolution, as Pakistan was among the first countries to recognise the new Iranian government. In the aftermath of the hostage crisis in Tehran, the United States severed its ties with Iran, leading Iran to send its military officers and personnel to be educated at Pakistani military academies. Relations became difficult following the Soviet–Afghan War, when hundreds of foreign fighters (mostly Sunni Arabs) arrived in Pakistan to take part in the Afghan Jihad. Pakistan President Zia-ul-Haq's military administration policy reflected extremist views towards the Shiites and caused religious tensions to rise between Sunni and Shiites in Pakistan, much to the discomfort of Iran. During the Iran–Iraq War, the Arab countries and the United States, who were supporting Iraq, pressured Pakistan to discontinue its covert support and military funding for Iran.