The Anonymous hackers group claims it has broken into the website of a US company whose tear gas has been used against demonstrators in Egypt.
In a statement posted on the internet, hackers accused Combined Systems of being war profiteers who sell "mad chemical weapons to militaries and cop shops around the world."
Anonymous has claimed a series of web attacks worldwide and has increasingly focused on security companies, law enforcement and governmental organizations. The group has often worked in tandem with the Occupy protest movement in the US and has expressed solidarity with the pro-democracy activists across the Arab world.
Anonymous said it had targeted Combined Systems because it was supplying weaponry used to "to repress our revolutionary movements."
The hackers also claimed to have stolen and published personal information belonging to clients and employees of the firm. Allegedly intercepted emails were pasted onto the bottom of the statement; one of them appeared to be a warning that Combined Systems' site had been sabotaged.
"Looks like our web hosts got hacked," the email says.
The company says sells a variety of security items, including aerosol grenades, sprays and handcuffs. Journalists and activists have reported finding the company's tear gas canisters at Egypt's Tahrir Square, where authorities have repeatedly cracked down on demonstrators with deadly force.
Last year human rights group Amnesty International said that Combined Systems had delivered 46 tons of ammunition - including chemical irritants and tear gas - to the Egyptian government in three separate shipments.
Amnesty pleaded with the US government to stop the shipments, which it said should be suspended "until there is certainty that tear gas and other munitions, weaponry or other equipment aren't linked to bloodshed on Egyptian streets."
Anonymous indicated that its attack had been timed to coincide the one-year anniversary of the uprising in Bahrain, the Gulf country hardest hit by upheaval during the so-called "Arab Spring" protests that began last year.