Knife attack on California bus

The attack caused the bus to run off the road

Two people have been killed after a passenger on a Greyhound bus slashed at the throat of the driver with a pair of scissors as the vehicle travelled along a California highway.

More than 20 people were injured when the Greyhound bus left the road, flipped over and slid 150 metres (500 ft) into a cotton field near the town of Fresno, 300 kilometres south of San Francisco.

"The attack appeared to be completely unprovoked," Lieutenant Margaret Mims of the county sheriff's department told ABC television on Tuesday.

Police have arrested a suspect they identified as 27-year-old Arturo Martinez and charged him with two counts of murder and one count of attempted murder.

No motive

They described the suspect as a transient from the Los Angeles area, but police said there was no indication of a motive for the attack.

The incident happened as the bus was travelling at about 70 mph (113 km/h) along Interstate 5 in Fresno County near the town of Coalinga, en route from Los Angeles to San Francisco.

Two women were killed at the scene. Although initial reports suggested the bus driver was among the dead, police say he is in hospital in a serious condition.

Witnesses said that at about 2100 local time (0400 GMT), a man rose from his seat, walked up the aisle to the driver and attacked him.

A passenger speaks to an emergency worker

"The driver was actually cut in the neck," Lieutenant Mims said. "He struggled, tried to defend himself and lost control of the bus."

Police said they had no reason to believe the attack had anything to do with terrorism.

"If somebody is thinking terrorist or hijacking or anything like that, we don't have any reason to believe that's the case," Lieutenant Mims said.

Previous attack

The attack comes almost a year to the day since a driver on a bus in the southern state of Tennessee had his throat cut by a passenger, causing a crash in which six people were killed.

A Greyhound spokeswoman said Monday's incident underscores the need for the US Congress to approve a bill to give bus companies more money for security measures.

The company already uses metal detectors and video cameras at some of its terminals.

Greyhound Lines, the last remaining nationwide bus service in the US, carries more than 25 million passengers a year.