The Israeli Air Force (IAF) first received AH-64As in 1990, for a fleet of 42 by 2000. The IAF's choice to buy Apaches over upgrading its AH-1 Cobra attack helicopters was controversial. In 2000, Israel was interested in acquiring up to 48 AH-64Ds, but U.S. reluctance to share the source code complicated the prospect. In April 2005, Boeing delivered the IAF's first AH-64D. In 2001, the U.S. government was allegedly investigating misuse of the Apache and other U.S.-supplied military equipment against Palestinians. In 2009, the sale of six AH-64Ds was reportedly blocked by the Obama Administration, pending interagency review, over concerns they may pose a threat to civilian Palestinians in Gaza. In IAF service, the AH-64A was named "Peten" (, for Cobra), while the AH-64D was named "Saraph" (, for venomous/fiery winged serpent).