Hector Xavier Monsegur, the suspected leader of the hacking group LulzSec has pleaded guilty to carrying out high profile attacks on several companies while other members of the group have been arrested, US law enforcement official says.

Hector Xavier Monsegur had been charged with conspiracy to engage in computer hacking according to unsealed court papers filed in Manhattan.

The charges were filed via “a criminal information” and the suspect – nicknamed Sabu – had co-operated with the government, Reuters reported.

US law enforcement officers have said at least three members of the hacking group had been arrested.

Irish police added that they have arrested one of five men being sought in connection with the group and are holding him at a south Dublin police station.

Charges against other suspects are expected to be made public later.

Hector Xavier Monsegur, the suspected leader of the hacking group LulzSec has pleaded guilty to carrying out high profile attacks on several companies while other members of the group have been arrested

LulzSec, which is linked to the online activist group Anonymous, had claimed responsibility for attacks against eBay and Sony Pictures among others.

Last month Anonymous published a recording of a private telephone conversation between FBI agents and London detectives talking LulzSec suspects.

Fox News reported that one of Lulzsec’s leading members had helped the bureau gather evidence against his associates.

Fox quoted one FBI official as saying: “This is devastating to the organisation… we’re chopping off the head of LulzSec.”

Prof. Alan Woodward, from the University of Surrey’s department of computing noted that LulzSec had been quiet since the middle of 2011 following an attack on Paypal.

“Judging by the level of activity this morning, where hackers have been pasting personal information about the person reported as having turned witness to implicate other hackers, it would appear that there is a considerable rift inside these groups,” he said.

“The hackers are certainly acting as if they feel they have been betrayed by one of their own.”