A police transport van crashed into another vehicle on a suburban Phoenix freeway on Wednesday, injuring 15 prisoners, officials said.
Five inmates and the van's driver suffered serious but non-life-threatening injuries in the crash that happened around noon Wednesday, said Forrest Smith, a spokesman for the Mesa Fire Department. The 10 other prisoners sustained minor to moderate injuries.
Another Mesa police employee was in the van when it crashed on US-60 near the Loop 101, but that person wasn't hurt, officials said.
Smith told NBC News the van collided with a smaller "construction-style truck" with a flatbed. The driver of the transport van had to be mechanically extricated, he said.
The cause of the crash isn't immediately clear, but it shut down the westbound lanes of the freeway.
The incident was under investigation by the Arizona Department of Public Safety, Smith said.