BlackBerry maker RIM has raised eyebrows with a statement saying it was helping police following reports rioters used its messaging system to communicate.
Riots across London over the past two days were sparked after police allegedly shot a man during an arrest attempt.
The BlackBerry Messenger (BBM) service was popular among teenagers in Britain, with a recent report by Ofcom saying BlackBerry handsets were most common among younger users.
News reports claimed rioters and looters used BBM to alert others where to go, but it was unclear exactly how many BlackBerrys, other handsets or social networks were actually being used.
RIM posted two lines on Twitter, saying it was working with police regarding the riots.
"We feel for those impacted by this weekend's riots in London," it said. "We have engaged with the authorities to assist in any way we can."
Asked for additional comment, RIM only added that it normally works with police. "As in all markets around the world where BlackBerry is available, we cooperate with local telecommunications operators, law enforcement and regulatory officials.
"Similar to other technology providers in the UK we comply with The Regulation of Investigatory Powers Act and cooperate fully with the Home Office and UK police forces."
If under court order, any firm can be required to hand over data, but it's unclear why RIM felt the need to announce it, or if the police had requested assistance.
RIM has said it had no plans to shut down the BBM service.
Meanwhile, the Metropolitan Police has warned it will target social-networking users who "incite" violence.
Deputy Assistant Commissioner Stephen Kavanagh said messages posted on Twitter had been "really inflammatory" and "inaccurate", according to a report in The Independent.
Kavanagh said the police would "absolutely" arrest anyone inciting violence via the social-networking site.
"That investigation is already under way and that is exactly the sort of thing we are looking at," he said.