At least four people were killed on Thursday when a sightseeing balloon with 32 people on board crashed on the outskirts of the Slovenian capital Ljubljana, state television Rtvslo reported. Of 21 people injured eight - including one child - were in critical condition, the broadcaster said. Witnesses said the balloon, which had a pilot and co-pilot, was caught by sudden gusts of wind when it slammed into a tree and caught fire. Some of the people on board jumped from the balloon to save themselves from the blaze, they said. All of the injured suffered burns. Doctors said some patients also had fractured limbs and broken backbones. Among the passengers were several foreigners, including one British woman and three Italians. Their condition was not immediately clear.