* Gunman thought to be psychologically disturbed
* Man fired into crowd, victims shot at random
An apparently deranged gunman armed with a Kalashnikov shot dead three people and injured a fourth in the head as he fired at them on a street in southern France on Thursday, officials said.
Police arrested a suspect aged about 20 near the site of the shooting. The young man had a record of minor run-ins with authorities, in particular for possessing banned guns, police officials in the city of Marseille said.
The victims appeared to be chosen at random as the suspect, who was thought to be psychologically disturbed, was not known to have had any previous contact with any of them.
"It would seem that this person had a high-calibre weapon, a Kalashnikov, and fired at the crowd," Interior Minister Manuel Valls later told journalists in Paris.
"It's very worrying and it once again shows the problem of weapons circulating around," he added, speaking shortly before leaving for the site of the shooting in Istres, 20 km (12-miles) west of Marseille.
France's second-biggest city has seen a spate of drug-related shootings with an influx of weapons from eastern Europe after the Balkans wars contributing to a rise in gun violence.