One of the biggest cyber-attacks is causing global internet services to slow down, and the situation could get worse, after a major anti-spam agency was targeted.

The organization Spamhaus, located at London and Geneva and deals with removing unwanted "spam" messages that may be sent to users' e-mails, announced that it is facing "distributed denial of service" attacks (Distributed Denial of Service or DDoS) on an unprecedented scale for more than a week.

"Based on the scale of the attacks, which has been assessed at 300 Gigabits per second, we can confirm that this is one of the largest DDoS attacks to date," the cyber security company said in a statement Kaspersky Lab. "There are likely to be further problems on an even larger scale as the attacks escalate."

"They've targeted any part of the internet infrastructure they think they can hit," he told the broadcaster. BBC its managing director Spamhaus, Steve Linford.

Those in charge of DDoS Attackers typically attack websites by flooding servers with messages from multiple systems.

“If there are a few computers sending large amounts of messages, this can be easily dealt with through filtering. But when literally thousands of systems are involved in the attack, it makes filtering almost impossible," he told the agency. Reuters Paul Vlisidis, directors of the company's cyber security technical team NCC.