An Egyptian bus driver has shot dead six construction workers travelling in his vehicle, security officials say.

埃及安全官员称，一位公交车司机射杀了六名乘坐他车辆旅行的建筑工人。

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The motive for the attack remains unclear

They said the driver was taking the employees to a site near Cairo when he stopped the company bus, turned round and opened fire, also wounding six others.

The gunman was arrested. The motive for the attack remains unclear.

The BBC's Jon Leyne in Cairo says first indications are the attack was probably not politically motivated.

Some reports suggested the driver was depressed³（沮丧的，萧条的） after being transferred to a new position.

The driver worked for a company called Arab Contractors⁴, one of Egypt's biggest building firms.

The company said he was taking 22 labourers and other employees to its site near Cairo when he stopped the vehicle.

"The passengers were shocked to see driver Mahmud Taha Ahmad Sueilem, 54, pull out an automatic weapon from under his seat and start firing indiscriminately（任意地） on the passengers," it said in a statement quoted by AFP news agency.

Six other employees were injured, the provincial⁵ governor said. Earlier reports said 16 people had been wounded.

A security source cited（引用） by Reuters news agency said female passengers on the bus were not shot, adding that the victims included a finance manager and a department head.