At least 16 people have been killed in a hot air ballon crash in Texas.

It caught fire and came down in a field in Lockhart, south of Austin.

The cause of the crash has not been confirmed, but it burst into flames near power lines.

Margaret Wylie, an eyewitness who called 911 after the hot air balloon came down, described hearing popping sounds shortly before the craft was engulfed in flames. "I looked around and it was like a fireball going up."

Texas governor Greg Abbott said: "Our thoughts and prayers are with the victims and their families, as well as the Lockhart community."

May God's restorative strength & grace be with the families affected by the tragic hot air balloon crash. #txlege https://t.co/1d2oPDVtj8

— Greg Abbott (@GregAbbott_TX) July 30, 2016