Two Britons accused of major computer hacking plots are facing prosecution on both sides of the Atlantic.
Scotland Yard and the FBI simultaneously launched separate court proceedings against alleged members of online anarchists LulzSec.
British officers said the decision to charge Ryan Mark Ackroyd, 25, of Oak Road, Mexborough, Doncaster, and a 17-year-old youth from south London was "completely unrelated" to actions in America.
Ackroyd and another Briton, Jake Davis, were named in prosecution papers in New York just hours earlier.
The FBI also accused an Irish county councillor's son of tapping into a conference call the agency had with a string of international agencies investigating an international hacking ring.
Donncha O'Cearrbhail, whose online name is palladium, faces up to 15 years jail if found guilty of recording the transatlantic briefing on investigations into the Anonymous outfit and cyber crime.
A second Irish student, Darren Martyn, 25, from Galway, with the hacker name pwnsauce, has also been named on the charge sheet published by the US Attorney's office.
The Metropolitan Police has now charged four suspects - including Davis, 18 - over the alleged hacking of websites including the UK's Serious Organised Crime Agency.
Ackroyd and the 17-year-old are accused by British prosecutors of two counts of conspiracy to "do an unauthorised act with intent to impair or with recklessness impairing of an operation of a computer", the force said.
Ackroyd will appear on bail at Westminster Magistrates' Court on March 16 while the 17-year-old will appear at West London Youth Court on March 13.
Davis, 18, and Ryan Cleary, 19, appeared in court last autumn charged with similar offences.
The American charges were laid out in court papers unsealed in federal court in New York as authorities said that a sixth person, Hector Xavier Monsegur, of New York, had already pleaded guilty.
The FBI court papers said the offence by O'Cearrbhail took place in January.
O'Cearrbhail, 19, from Birr, Co Offaly, was one of two men arrested last September after the Fine Gael website was shut down following a denial of service attack in January 2011.
Papers on the FBI website said: "Because the Garda officer had forwarded work emails to a personal account, O'Cearrbhail learned information about how to access a conference call that the Garda, the FBI, and other law enforcement agencies were planning to hold on January 17, 2012 regarding international investigations of Anonymous and other hacking groups.
"O'Cearrbhail then accessed and secretly recorded the January 17 international law enforcement conference call, and then disseminated the illegally-obtained recording to others."
The FBI papers added that Ackroyd, Davis, from Shetland, and Martyn "each are charged with two counts of computer hacking conspiracy. Each conspiracy count carries a maximum sentence of 10 years in prison".
LulzSec is a spin-off of the loosely organised hacking collective Anonymous.
The group are accused by the FBI of attacking governments and corporations in Britain and around the globe.
The charges were issued in New York after its ringleader Monsegur turned against his comrades and began working as an informant, authorities said.
Monsegur was portrayed as one of the world's most-wanted computer vandals known in the hacking underworld as "Sabu".
Authorities said he formed an elite hacking organisation last May and named it Lulz Security or LulzSec. "Lulz" is internet slang that can be interpreted as "laughs", "humour" or "amusement".
Monsegur was charged with conspiracy to engage in computer hacking, among other offences. Authorities said he pleaded guilty on August 15.
The court papers said he participated in attacks over the past few years on Visa, MasterCard and PayPal, government computers in Tunisia, Algeria, Yemeni and Zimbabwe, Fox Broadcasting, the Tribune, PBS and the US Senate.
According to the court papers, he was an "influential member of three hacking organisations - Anonymous, Internet Feds and Lulz Security - that were responsible for multiple cyber attacks on the computer systems of various businesses and governments in the United States and throughout the world".
Monsegur and others planted a fake story in retaliation for what they perceived to be unfavourable news coverage of WikiLeaks on the PBS news programme Frontline, the court papers alleged.