SANAA- A Yemeni fighter jet crashed in the centre of the capital Sanaa on Tuesday, killing at least six people, medical sources said.The ministry said in a text message that the warplane had been on a training flight when it came down in a western residential district. Pictures of the crash on social media sites showed one body near burning wreckage of the aircraft. Several cars were on fire and debris littered the street.A security official said without elaborating that the pilot had ejected from the plane. A military official said the aircraft was a Russian SU-22.