Two men have been arrested in the UK for participating in cyber attacks performed by the hacktivist groups LulzSec and 'Anonymous' under the cover of the online identity "Kayla."

The two men, aged 24 and 20, were arrested separately by the Metropolitan Police Service's Central e-Crime Unit on Friday for conspiring to commit offenses under the Computer Misuse Act 1990.

"Kayla" had claimed to be a 16-year-old girl who reportedly played a key role in a cyber attack against the software security firm HBGary Federal. Members of 'Anonymous' defaced HBGary's website and stole 44,000 company e-mails in February after former CEO Aaron Barr told the Financial Times that he'd identified the "core leaders" of the group and had information that could lead to their arrest.

Barr resigned shortly after the cyber attack.

The emails revealed that the company had concocted plans to attack WikiLeaks on behalf of Bank of America and collected information on progressive political figures for the U.S Chamber of Commerce.

"Kayla" was also believed to be a key figure of LulzSec, a group that claimed responsibility for a hacking rampage targeting the websites of the Central Intelligence Agency, PBS, the U.S. Senate, Sony and others.

The arrests were part of a coordinated investigation involving the FBI, South Yorkshire Police, and other law enforcement agencies into the activities of 'Anonymous' and LulzSec.

"The arrests relate to our enquiries into a series of serious computer intrusions and online denial-of-service attacks recently suffered by a number of multi-national companies, public institutions and government and law enforcement agencies in Great Britain and the United States," Detective Inspector Mark Raymond said in a statement.

"We are working to detect and bring before the courts those responsible for these offences, to disrupt such groups, and to deter others thinking of participating in this type of criminal activity."