BUS DRIVER SHOOTS CAIRO WORKERS
They told Egyptian media that the driver was taking the employees to a site near Cairo when he stopped the company bus, turned round and opened fire, also wounding several others.
The gunman was arrested. The motive for the attack remains unclear.
Egypt has suffered attacks from militants in the past, but political violence has abated in recent years.
The BBC's Jon Leyne in Cairo says first indications are that Tuesday's attack was probably not politically motivated.
Some reports suggested the driver was depressed after being transferred to a new position.
A security official told AFP news agency the driver worked for a company called Arab Contractors and was taking 22 labourers and other employees to their site near Cairo when he stopped the vehicle.
“He then took out an automatic weapon and opened fire at the passengers, killing six on the spot and wounding 16, who have been taken to hospital,” the official said.
Another security source cited 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.