Police accused the three men of temporarily blocking access to some Sony websites, Reuters reported. The men were not responsible for the recent Sony PlayStation Network attacks, according to the report.
All three men were released without bail, pending formal charges, a police spokeswoman not identified per department policy told the New York Times.
One of the men had a computer server in his apartment in Gijon. Police said the computer was used for attacks against government sites in Egypt, Algeria, Libya, Iran, Chile, Colombia and New Zealand, according to the New York Times.
Police said the investigation began in October 2010 after a complaint by the Spanish Ministry of Culture when its website suffered a Denial of Service (DDoS) attack, according to CNN.
These are the first arrests of alleged members of Anonymous in Spain, according to the report.
Anonymous has also publicly taken responsibility for attacks against PayPal, Visa and others because those institutions acted to block donations to whistleblower-site WikiLeaks.