WASHINGTON, Jan 8: A US Air Force C-5 cargo plane carrying 63 passengers and crew members was apparently hit by a surface-to-air missile on Thursday as it took off from Baghdad international airport , but it managed to land safely, a senior US defence official said.

"It looks like its number four engine was hit by a surface-to-air missile, but it was able to turn around, come back and land," the official said, speaking on condition of anonymity.

An investigation into the incident was under way. Earlier, the air force said in a statement that the C-5 declared an inflight emergency "because of excessive engine vibrations in their number four engine," the air force said in a statement.

"The aircraft had just departed the airport when the problem occurred. The crew was able to land safely. There were 63 passengers and crew members on board the aircraft. No injuries were reported," it said.

It would be the third time since May 1, when major combat operations were declared over, that a plane has been hit by a surface-to-air flying out of Baghdad international airport.

On Dec 10, a defence official in Washington said an Air Force C-17 cargo and troop transport plane was hit by a surface-to-air missile after takeoff from Baghdad with a crew of three and 13 passengers.

On Nov 22, a DHL cargo plane was hit by a shoulder-fired SA-14 surface-to-air missile as it took off from Baghdad airport. DHL temporarily suspended flights into Iraq after the incident. -AFP