The USSR's invasion of Afghanistan was only one sign of insecurity in the region, also marked by increased American weapons sales, technology, and outright military presence. Saudi Arabia and Iran became increasingly dependent on American security assurances to manage both external and internal threats, including increased military competition between them over increased oil revenues. Both states were competing for preeminence in the Persian Gulf and using increased revenues to fund expanded militaries. By 1979, Saudi arms purchases from the US exceeded five times Israel's.