Jacques Villeneuve and Juan Pablo Montoya face a two-race ban if their bitter feud breaks out again.

Formula One chief Bernie Ecclestone has stepped into the row, telling them he does not want the open hostility to escalate into another clash.

The warning came after they had to be pulled apart during the drivers' briefing at the Canadian Grand Prix in Montreal.

Villeneuve grabbed Montoya around the scruff of the neck after the Colombian is alleged to have told his fellow driver he had 'killed' someone this season.

The allegation refers to the opening race of the campaign in Melbourne when Villeneuve's British American Racing car collided with the Williams of Montoya's team-mate Ralf Schumacher.

The car catapulted into the air and a loose wheel was sent smashing through a gap in the safety fencing killing volunteer marshal Graham Beveridge.

Ecclestone, who had already spoken to Villeneuve, said before a meeting with Montoya: "Now I have to speak to Montoya before the situation escalates."

Race Director Charlie Whiting has also warned Villeneuve and Montoya, who will start the race alongside each other on the grid, that they face a ban.

"I have spoken to both drivers and told them that if there is another little incident, one or both will watch two races from outside," said Whiting.

The feud began on Friday when Villeneuve accused Montoya, who like his rival came into F1 after winning the CART series title in the United States, of blocking him on the track during practice.

But Montoya angrily hit-back and claimed Villeneuve had brake-tested him at a chicane when he did overtake him during the session.

Montoya is alleged to have told Villeneuve at the drivers' briefing, "Do that again and I will put you in the f****** wall."

Villeneuve is said to have responded: "I will put you in the f****** tree."

Reports say Montoya replied: "F*** you, you have already killed someone this season."

At this point, Villeneuve grabbed Montoya around the top of his overalls and the pair had to be pulled apart.