Britain's interior minister and police met social media companies Thursday in the wake of riots this month to discuss how to stop gangs using the networks to plan social unrest.

But the government said it had not sought extra powers to clamp down on social media at the meeting despite suggestions from ministers in the immediate aftermath of the unrest that they might try to shut down networks during future trouble.

Home Secretary Theresa May chaired the talks with companies including the makers of the BlackBerry smartphone, whose encrypted chat service took much of the blame for allowing rioters to coordinate the four nights of unrest in England.

Social networking sites Facebook and Twitter were also represented at the meeting in London, said a statement from the Home Office.

"The discussions looked at how law enforcement and the networks can build on the existing relationships and cooperation to prevent the networks being used for criminal behaviour," said a ministry spokeswoman.

The idea of a total shutdown during future trouble was floated by Prime Minister David Cameron in the wake of the riots but the government did not request extra powers at Thursday's talks.

"The government did not seek any additional powers to close down social media networks," said the spokeswoman.

The Canadian firm that makes BlackBerry, Research in Motion, described the meeting as "positive and productive."

"We were pleased to consult on the use of social media to engage and communicate during times of emergency," said a company statement.

A Facebook spokeswoman welcomed the fact the talks focused on keeping "people safe rather than about imposing new restrictions on internet services."

There were calls to temporarily suspend BlackBerry's messenger service during the riots that first erupted in the London district of Tottenham on August 6 and spread to other cities in England, leaving five people dead and shops and flats looted and burned.

David Lammy, an opposition lawmaker from Tottenham, urged a shutdown, saying criminals were using the service to outwit police. The messenger service remained up and running throughout the unrest, however.

A number of people have appeared in court in recent weeks for organising or attempting to incite riots on social networks.

Two men, Perry Sutcliffe-Keenan, 22, and Jordan Blackshaw, 21, were each jailed for four years for trying to incite riots in towns in northwest England through Facebook, even though no-one heeded their call.