Seven people including two British tourists were wounded Sunday in Paris after they were attacked by a man armed with a knife and an iron bar, according to police and other sources.

A source close to the inquiry said the suspect, believed to be an Afghan national, has been arrested.

"Nothing at this stage shows signs of a terrorist nature in these assaults," the source said, adding that the attacker had targeted "strangers in the street".

Of the seven wounded, four are in a critical condition, police said.

The incident took place just after 11:00pm (2100 GMT) on the banks of a canal in the northeast of the capital.

A security guard at one of two cinemas on either side of the Bassin de la Villette, part of the Canal de l'Ourcq, said he saw a man who had already assaulted people being chased by two other men who tried to stop him.

"He had an iron bar in his hand which he threw at the men chasing him, then he took out a knife," he told AFP.

Another eyewitness, 28-year-old Youssef Najah, said he was walking along the canal near a bowling green when he saw a man running and holding a knife about 25-30 cm (10-11 inches) long.

"There were around 20 people chasing him. They started throwing Petanque balls at him," Najah said, referring to the sport popular in France also known as boules.

"Around four or five balls hit him in the head, but they weren't able to stop him," he added.

According to the same witness, the attacker then dived into an alleyway, where the man "tried to hide behind two British tourists. We said to them: 'Watch out, he has a knife". But they didn't react".

The pair were then attacked, he said.