The "Anonymous" hacking group on Tuesday claimed to have shut down the website of security firm Combined Systems, which it accused of providing the tear gas used in crackdowns on protests.

The statement circulated in forums used by the shadowy "hacktivist" group could not immediately be confirmed. The Combined Systems website appeared to be down, and the company could not immediately be reached for comment.

"You war profiteering all crazy, selling mad chemical weapons to militaries and cop shops around the world, thinking you will get away unscathed by the rising tides of insurrection?" the statement said.

"Think again... Combined Systems, lay down your arms: you just lost the game."

The statement posted on YourAnonNews -- a Twitter account used by the group -- went on to claim that hackers had taken phone numbers, emails, passwords and other information from Combined Systems employees and clients.

Last week the website of the Central Intelligence Agency was briefly inaccessible after Anonymous claimed to have knocked the US spy agency offline.

In January the group briefly took down the websites of the US Justice Department and the Federal Bureau of Investigation in retaliation for the US shutdown of file-sharing website Megaupload.

Most Anonymous cyberattacks are distributed denial of service attacks in which a large number of computers are commanded to simultaneously visit a website, overwhelming its servers.

Nortel was penetrated by hackers for decade: report
New York (AFP) Feb 14, 2012 - Bankrupt Canadian telecom company Nortel was penetrated for at least a decade by hackers believed to have been operating from China, the Wall Street Journal reported Tuesday.

The hackers, using seven passwords stolen from top executives, including the company's CEO, downloaded technical papers, research and development reports, employee emails and other documents, the Journal said.

It cited Brian Shields, a former 19-year veteran of the firm who led an internal investigation, as saying: "They had access to everything... They had plenty of time. All they had to do was figure out what they wanted."

Shields said the hackers also hid spying software so deeply on employee computers that it took the company years to figure out the extent of the problem.

The revelations highlight the threat posed by Chinese hackers, whom US intelligence said were the world's "most active and persistent perpetrators" of economic espionage in a report submitted to the US Congress last November.

The Journal quoted the Chinese embassy as denying allegations of cyberspying, saying such attacks are "transnational and anonymous."

The Journal's story came out hours before Chinese Vice President Xi Jinping -- expected to become China's next president in 2013 -- was to meet US President Barack Obama at the start of a week-long US tour.

Nortel, once Canada's largest company, filed for bankruptcy in 2009.