United States President George Bush has apologized to Britain over the US failure to declare that two aircraft were carrying missiles bound for Israel when they refueled at a Scottish airport, Prime Minister Tony Blair's spokesman said Friday. Britain's Civil Aviation Authority is investigating whether Washington had applied for the necessary exemptions to carry hazardous material on two chartered Airbus A310 cargo planes that refueled at Glasgow's Prestwick Airport last weekend. "President Bush did apologize for the fact that proper procedures were not followed," Blair's spokesman told reporters following talks between the two leaders in Washington. "It was a gracious thing to do." Britain's Foreign Secretary Margaret Beckett had earlier complained to US Secretary of State Condoleezza Rice on the sidelines of international talks in Rome on Wednesday, warning that British procedures had been violated. Opposition lawmakers had urged Blair to demand an apology from Bush after learning that the two aircraft were carrying 28 GBU28 laser-guided missiles bound from the United States to Israel. Two other US flights carrying "hazardous" cargo bound for Israel are set to refuel at Prestwick Airport this weekend, aviation authorities said. It was not immediately clear what would be on the planes, but the contents needed a special exemption from aviation authorities, which was granted.