LONDON (AFP) - A British teenager who accessed the e-mail accounts of top US intelligence and security officials including the head of the CIA was sentenced to two years in prison on Friday (April 20).

Kane Gamble, 18, founder of Crackas With Attitude, will serve his sentence in a youth detention facility.

"This was an extremely nasty campaign of politically motivated cyber terrorism," judge Charles Haddon-Cave said at the sentencing at London's Old Bailey criminal court.

"The victims would have felt seriously violated," Haddon-Cave said, adding that Gamble had "revelled" in the attacks.

Gamble was accompanied by his mother in court.

He was 15 and 16 when, from his bedroom in Coalville, central England, he managed to impersonate his targets to get passwords and gain highly sensitive information.

He impersonated then Central Intelligence Agency chief John Brennan in calls to the telecom companies Verizon and AOL.

Several sensitive documents were reportedly obtained from Brennan's private email inbox and Gamble managed to get information about military and intelligence operations in Iran and Afghanistan.

"It also seems he was able to successfully access Mr Brennan's iCloud account," prosecutor John Lloyd-Jone said earlier.

Gamble called AOL and initiated a password reset, and took control of the iPad of Brennan's wife.

Gamble also targeted then US secretary of homeland security Jeh Johnson and made calls to his phone number.

He left Johnson's wife a voicemail saying "Am I scaring you?" and managed to get a message to appear on the family television saying: "I own you".

Other targets included then US president Barack Obama's deputy national security adviser Avril Haines, his senior science and technology adviser John Holdren, and FBI special agent Amy Hess.

Gamble gained extensive unauthorised access to the US Department of Justice network and was able to access court case files, including on the Deepwater oil spill.

The British teenager gave some of the material he managed to access to WikiLeaks and boasted that he had a list of all Homeland Security employees.

Gamble was arrested at his home on February 9 last year at the request of the FBI.

He claimed he was motivated to act out of support for the Palestinians, and due to the United States "killing innocent civilians", the prosecutor said.