Comms Council U.K. recently announced that several U.K. providers of voice over internet protocol (VoIP) services were targeted in recent weeks by a distributed denial of service (DDoS) attack.

While VoIP firms have been targeted for alleged blackmail, Comms Council U.K. claimed that the DDoS attacks on British VoIP firms had taken place within the last four weeks and that this “appears to be part of a coordinated extortion-focused international campaign by professional cyber-criminals.”

In an interview with the BBC, a spokesman for Britain’s Comm Council, who provided further details of the issue, described the incident as “unprecedented.”

He explained: “We have never seen anything like it since we were established back in 2004. Ransom threats have been made to numerous providers and an overall threat has been made to the entire industry. The attackers have started down that path, with attacks underway. We’re aware that some networks have been experiencing problems recently. We are in contact with them to establish the scale and cause of the problem, and also liaising closely with the UK Government and National Cyber Security Centre.”