A car, believed to be carrying 19-year-old Ryan Cleary (C) hidden under a jacket by police officers, leaves Westminster Magistrates Court in central London. Cleary, charged with attacking websites as part of an international hacking group, was remanded in police custody by a court Thursday while he assists a police investigation.

A British teenager charged with attacking websites as part of an international hacking group was remanded in police custody by a court Thursday while he assists a police investigation.

Ryan Cleary, 19, did not enter any plea to five charges under the Computer Misuse Act when he appeared at City of Westminster Magistrates Court in central London.

"He has been assisting with inquiries so far and is keen to continue doing so," defence lawyer Ben Cooper told the court.

Police arrested Cleary on Monday at his home in Wickford, southeast England, as part of a probe by Scotland Yard and the US (FBI) into the Lulz Security .

Lulz has claimed responsibility for a month-long rampage against international businesses and government agencies, including the CIA and Senate in the United States and electronics giant Sony.

British police on Wednesday charged Cleary with targeting the website of Britain's Serious Organised Crime Agency -- the British equivalent of the FBI -- with a Distributed (DDoS) attack.

DDoS attacks overwhelm websites with requests, causing them to be slow or inaccessible.

He was charged with similar attacks on the website of the International Federation of the Phonographic Industry (IFPI) in November and the British Phonographic Industry (BPI) on October, it said.

Cleary faces two further charges of creating a "botnet" or network of computers to carry out .

Lulz has denied that Cleary was part of the group.