At least four people have been killed and 39 others have been injured after a suspension bridge collapsed in Indonesia's East Kalimantan province on Borneo island on Saturday. A police spokesman said Sunday that as many as 40 others could still be missing after the 720-metre bridge snapped. A local official had earlier said five people were killed. The bridge was undergoing repairs when it collapsed, sending buses, cars and motorcycles plunging into the Mahakam river below, said Sutopo Nugoroho, a spokesman for the National Disaster Management Agency. The cause of the accidents was being investigated, though officials said it was believed to be related to the repair work, according to a report of the German Press Agency "DPA". A national police spokesman, Boy Rafly Amar, said local officials estimated 40 people were still missing, possibly trapped in vehicles under the water.