DHAKA (AFP) - At least 25 people were killed and many more injured when a packed bus slammed into a tree in Bangladesh early on Thursday.

The driver told a local television station he had lost control of the bus after being attacked by robbers armed with knives who tried to grab the steering wheel. The police had earlier said the driver had been killed in the collision.

Local police chief Nazmul Islam said the accident occurred during an overnight journey on the Barisal-Dhaka highway. "In all 22 people died on the spot and later three more died in the hospital," he told AFP, adding that 19 of the roughly 50 people on board were injured, some critically.

Police have launched an investigation into the cause of the crash.

Bangladesh has one of the world's highest death rates from road accidents, mainly due to the poor state of roads and vehicles and a failure to comply with traffic regulations.