Philippine police and the FBI have arrested four people thought to have been paid by a militant Saudi Arabian-based group to hack into US telecom AT&T's system.
The Philippines' Criminal Investigation and Detection Group (CIDG) said those arrested in Wednesday's operation in Manila with the Federal Bureau of Investigation were paid by the same group the FBI said had funded the November 2008 attacks in Mumbai.
"The hacking activity resulted in almost $US2 million ($2.04 million) in losses incurred by the company," the CIDG said in a statement.
It did not name the group who its said had funded the Mumbai attacks, but India has blamed the militant Pakistan-based Lashkar-e-Taiba (LeT) for carrying out the attacks which killed 166 people.
AT&T, the second-largest US mobile provider, said it "ended up writing off some fraudulent charges that appeared on customer bills" but did not comment on the $2 million figure.
"AT&T and its network were neither targeted nor breached by the hackers," AT&T spokeswoman Jan Rasmussen said.
"AT&T only assisted law enforcement in the investigation that led to the arrest of a group of hackers."
Police said the suspects had hacked into the trunk-lines of different telecom companies, including AT&T, with revenues diverted to accounts of the unnamed Saudi-based group.
Earlier this week, AT&T said it was investigating an attempt to access customer information, but did not believe any accounts had been breached.
The CIDG said the FBI sought the help of its Anti-Transnational and Cyber Crime Division (ATCCD) in March after they found the Saudi group had targeted AT&T using the hackers.
Among the four arrested was 29-year-old Paul Michael Kwan, who ATCCD chief Police Senior Superintendent Gilbert Sosa said had been arrested in 2007 after the FBI launched an international crackdown on groups suspected of financing militant activities.
Sosa said in the statement the Filipinos were being paid by a group originally run by Muhammad Zamir, a Pakistani arrested in Italy in 2007. He said Zamir was a member of Jemaah Islamiah, a Southeast Asian militant network with links to al Qaeda.
"Zamir's group, later tagged by the FBI to be the financial source of the terrorist attack in Mumbai, India, on November 26, 2008, is also the same group that paid Kwan's group of hackers in Manila," Sosa said in the statement.
Last month, Philippine police said weak laws against cyber crime and poor technical capabilities had made the country an attractive base for organised crime syndicates involved in cyber pornography, cyber sex dens, illegal gambling, credit card fraud and identity theft.
(Reporting by John Mair in Manila and Jim Finkle in Boston; Editing by Nick Macfie)