FBI arrested hacker-activists from the group Anonymous, which earlier claimed responsibility for attacking MasterCard and Visa websites to assist WikiLeaks founder Julian Assange, U.S. media reported.
Various sources put the number of detainees at 14 or 16. Arrests were made in various U.S. states, including Florida, New Jersey and California.
FBI has also issued from 30 to 40 search warrants for the group's members, Fox News said.
Anonymous claimed responsibility for hacker attacks on websites of the U.S. Senate, the CIA, the Brazilian president and government and large corporations, such as Sony, telecoms giant AT&T, FOX Broadcasting Company, Visa and Master Card.