Hackers knocked offline a website run by the British police Serious Organized Crime Agency (SOCA), which targets organized crime in Britain and overseas.

Lulz Security, a loosely aligned hacker group that said it brought down the SOCA website on Monday, has gone after a long list of government and corporate websites. Like many others, the SOCA attack was likely a denial-of-service attack in which Lulz hackers bombarded the site with so many messages that it went offline.

We are aware of claims that the SOCA website has been attacked. The picture is not clear at this time, but we are investigating the matter with our service provider, said SOCA spokesman Richard Sellors.

SOCA's website went down for a bit on Monday but then was brought back up. On Monday evening, SOCA decided to take the site down for the night to take the pressure off its Internet service provider, which works with a variety of local businesses and organizations, said Sellors.

Sellors said that the affected website was purely for public information and that the hackers had no access to confidential data or information about ongoing operations.

Lulz has also hacked into a U.S. Senate server, and claimed responsibility for temporarily knocking offline the CIA's public website.

In a posting on Sunday, Lulz Security declared that the Lulz Lizard battle fleet is now declaring immediate and unremitting war on governments and security companies.

As part of that, Lulz, which derives its name from the plural variant of Internet slang for laugh out loud, urged its followers to hack into and deface government websites.

Top priority is to steal and leak any classified government information, including e-mail spools and documentation. Prime targets are banks and other high-ranking establishments, Lulz said in the statement on Sunday.

Lulz said it was working with Anonymous, a second international group of hackers.

The groups' stated goals have been murky. In the past, Anonymous has sought to support Julian Assange and Bradley Manning, who face charges after releasing U.S. government documents as part of Wikileaks.

Lulz has also sought to punish Sony Corp for failing to secure data but did so by releasing the data of Sony customers, exposing them to potential identity theft.

Meanwhile, a less public and more damaging series of hacks have targeted the International Monetary Fund and RSA, the security division of EMC Corp.

(Additional reporting by Georgina Prodhan in London; Editing by Gunna Dickson and Steve Orlofsky)