A massive fire involving a tanker truck on Detroit's border shut down Michigan's Interstate 94 in both directions on Wednesday, police said. The truck was carrying a petroleum product, said Michigan State Police spokesman Mike Shaw. He said it was unclear if the fire, reported around 11:15 a.m. EDT, was caused by a collision or by a mechanical problem. It also was unknown if there were any injuries or fatalities, Shaw said. The fire is at Detroit's border with Dearborn, Michigan. "Once they put the fire out, we'll try to determine what happened," Shaw said. Local television video showed at least one car was involved and suffered extensive fire damage. (Reuters)