At least 11 people were killed and dozens were injured after a head-on collision between a bus and a van in Brazil's central-west state of Mato Grosso, bordering Paraguay and Bolivia, the Federal Highway Police said. Initial investigations showed the two vehicles collided in the town of Sorriso, in the north of Mato Grosso, because the bus driver fell asleep at the wheel, the agency told local press on Tuesday. As many as 45 people were travelling on the bus bound for Sinop, nearly 500 kilometres away, Xinhua news agency reported. The bus driver was in serious condition, while the van driver suffered only minor injuries.