Islamic State (Isis) supporters have reportedly released the personal information of some 160 US military personnel in response to Anonymous's cyber campaign against the group.
Social media accounts tied to the pro-IS (Daesh) hacking group, Cyber Caliphate, leaked names and addresses of enlisted US Army and Marines on 11 December and claimed to possess information on 700 more military personnel, the Maryland-based SITE Intelligence Group reported.
It came on a day that Anonymous, a loose international coalition of hackers and activists, had designated an online "trolling day" against the Islamist fundamentalist group.
Social media users were encouraged to spam Twitter accounts belonging to IS sympathisers with images of goats.
Anonymous declared "war" on IS in the wake of the November terror attacks in Paris and claims to have taken down thousands of social media accounts linked to the jihadist group.
IS responded to the challenge by calling the hackers "idiots", and published tips on how the group's members and sympathisers could avoid being hacked.
Trump Towers cyber attack
Meanwhile, Anonymous has claimed responsibility for taking down the website of US presidential hopeful Donald Trump's iconic New York City skyscraper.
The website for the 68-storey Trump Towers went down for at least an hour on 11 December, with the hacking collective saying it was retaliation for his anti-Muslim comments.
Trump, the leading candidate for the Republican party's nomination, called for a blanket ban on Muslims entering the US in the wake of the deadly shootings in San Bernardino, California last week.
"Donald Trump, it has come to our attention that you want to ban all Muslims from entering the United States. This policy is going to have a huge impact," an Anonymous member said in a video posted on YouTube earlier this week.
"This is what Isis wants. The more Muslims feel sad, the more Isis feels they can recruit them.
"The more the United States appears to be targeting Muslims, not just radical Muslims you can be sure Isis will be putting that on their social media campaign."