Arusha, Tanzania ? An overloaded bus plunged off a bridge and into a river gorge in northern Tanzania on Friday, killing at least 54 people, police said.

Twenty people were injured.

The bus crashed into the Malala river 15 miles east of Mount Kilimanjaro, Regional Police Commander Balilo Matei said. The cause of the crash was under investigation.

Witnesses said the bus appeared to be speeding when the driver lost control.

Abbas Kandoro, the regional administrator, said more bodies could be uncovered by a crane that was headed to the scene to move the wreckage.

The bus was headed from Arusha, a tourism center 300 miles west of Dar es Salaam, to the mining town of Mererani.