PARIS — Prime Minister David Cameron of Britain said Thursday that the government, seeking to prevent a repeat of riots and looting in London and other British cities this week, might bar suspected troublemakers from using social media and other digital communications tools.

Mr. Cameron said that Theresa May, the Home secretary, would meet with executives of the Web companies Facebook and Twitter, as well as Research In Motion, maker of the BlackBerry smartphone, to discuss possible measures that could be put in place.

“Everyone watching these horrific actions will be struck by how they were organized via social media,” Mr. Cameron told Parliament during a special debate on the riots. “Free flow of information can be used for good. But it can also be used for ill.

“And when people are using social media for violence we need to stop them. So we are working with the police, the intelligence services and industry to look at whether it would be right to stop people communicating via these Web sites and services when we know they are plotting violence, disorder and criminality.”