People claiming to be hackers associated with Anonymous took credit on Twitter for the Tuesday site shutdown and encouraged sympathizers to keep Interpol's site offline by flooding its servers with traffic.
"They poked the hive," Twitter user AnonymousIRC wrote in a post monitored by United Press International.
"Interpol dubbed their attempt at arresting anons 'Operation Unmask' -- funny," anonymouSabu, also self-identified as The Real Sabu, posted on Twitter. "Let us assist them by unmasking and exposing Interpol agents."
The Interpol site was still down early Wednesday, with users seeing "Server not found" and "Problem loading page" messages instead, a UPI spot check indicated.
The Operation Unmask arrests in Argentina, Chile, Colombia and Spain were conducted with cooperation from those countries' governments, Interpol said.
The International Criminal Police Organization said it seized 250 pieces of information technology equipment and cellphones at 40 locations in 15 cities, as well as credit cards and cash from some alleged hackers.
It said the suspects ranged in age from 17 to 40, but the Spanish newspaper El Pais said Wednesday a 16-year-old girl was allegedly part of an Anonymous hacking group known as Sector 404.
Spain's RTVE network said an unidentified minor was released to parental custody.
Interpol said it began the operation a couple of weeks ago after a series of coordinated cyberattacks against Spanish political parties' Web sites, the Colombian Defense Ministry and presidential Web sites, Chile's national library and largest electric utility and other targets.
Arrested in Malaga, Spain, was an alleged hacker identified as FJBD, also known as Thunder or Pacotron, "allegedly responsible for administering and managing the IT infrastructure used by Anonymous in Spain and Latin America," Spain's National Police Corps said in a statement.
FJBD allegedly managed servers hosted in the Czech Republic and Bulgaria that were key for communication and coordination of Anonymous attacks, the statement said.
Arrested in Madrid was JMLG, or Troy, the alleged perpetrator of Spain's most notorious Anonymous attacks and private-data leaks, the statement said.
Anonymous is a loosely affiliated group of activist computer hackers first identified in 2003 with cyberpranks. It become increasingly associated with collaborative, international "hacktivism" in 2008, often in retaliation for anti-digital piracy campaigns by motion-picture and recording-industry trade associations.
Last month, Anonymous claimed responsibility for attacking the Web sites of the U.S. Justice Department and several major entertainment companies and trade groups in retaliation for the seizure of Megaupload Ltd., a popular online service that let users transfer movies and music anonymously.
The FBI charged seven people tied to Megaupload with running an international criminal enterprise centered on copyright infringement.
Anonymous is accused of knocking the CIA Web site offline Feb. 10.
A week earlier, hackers allegedly tied to the group intercepted a conference call between the FBI and Britain's Metropolitan Police Service, or Scotland Yard, and released a 16-minute recording of the call.
Hackers allegedly associated with Anonymous threatened to "shut the Internet down on March 31" by attacking servers that perform Internet switchboard functions.