Call for US to re-open UFO file

A group of former pilots and government officials has called on the US government to re-open an investigation into claims of UFO sightings.

Project Blue Book, run by the US Air Force, was stopped in the late 1960s.

The group, which includes former military officers from seven countries, all say they have seen a UFO or have conducted research into the phenomenon.

However, the Air Force says nothing has happened in the past four decades to justify resuming investigations.