Ellsworth Air Force Base officials have not yet found a cause for the fires that happened near Box Elder Thursday after a B-1B Lancer bomber was forced to land.

Ellsworth public affairs officials are not sure when a cause will be released.

The bomber landed after an in-flight emergency was declared shortly after 11 a.m. Thursday during a scheduled training sortie. The aircraft landed safely with no reported injuries. Several small spot grass fires were apparently caused by the bomber, but the fires were quickly extinguished.