Hackers took control of a FoxNews.com Twitter account Monday and sent six false tweets saying that U.S. President Barack Obama had been shot dead.
"Those reports are incorrect, of course, and the president is spending the July 4 holiday with his family," Foxnews.com said in a statement about the latest in a wave of high-profile cyber security breaches around the world.
"Hackers sent out several malicious and false tweets that President Obama had been assassinated," said the conservative media outlet owned by Rupert Murdoch's News Corp.
"The hacking is being investigated, and FoxNews.com regrets any distress the false tweets may have created," it said.
Obama is celebrating the July 4 Independence holiday with his family at the White House and was due to host military families to watch Fourth of July fireworks in the evening.
The White House and Secret Service both declined to comment on the incident.
The first hacked tweet appeared around 2 a.m. and said: "@BarackObama has just passed. The President is dead. A sad 4th of July, indeed. President Barack Obama is dead."
The next one, "@BarackObama has just passed. Nearly 45 minutes ago, he was shot twice in the lower pelvic area and in the neck; shooter unknown. Bled out."
Fox News Digital Vice President and General Manager Jeff Misenti said FoxNews.com was working with Twitter to address the situation as quickly as possible.
"We will be requesting a detailed investigation from Twitter about how this occurred, and measures to prevent future unauthorized access into FoxNews.com accounts," Misenti said.
A group calling itself The ScriptKiddies claimed responsibility for sending the tweets - including "#ObamaDead, it's a sad 4th of July" - from the "FoxNewspolitics" news feed before Twitter suspended its access.
In all some six false tweets were issued, saying Obama had been shot at a restaurant in Iowa while campaigning.
Obama was not in Iowa this weekend. He returned Sunday to the White House from a brief trip to Camp David in neighboring Maryland.
The Foxnews.com account hacking followed a wave of highly publicized cyber security breaches, including attacks on the bank Citigroup, Sony Corp., Apple and the U.S. Senate and Brazilian presidential websites.
Monday's breach raised questions about the integrity of news feeds on Twitter, which is increasingly used by news outlets as well as government officials as a way to reach readers and supporters.
Twitter spokeswoman Jodi Olson declined to say whether the company would add more security as a result of the attack, but stressed it was important for users to shield their profiles.
"We don't comment on specific accounts. In general, though, it's always good to remind people of the importance of actively protecting their account credentials," Olson said, recommending that all users have a strong password as a "starting point."
The FoxNews.com hacking came two days before Obama's first "Twitter town hall" where he will field tweeted questions about the economy and jobs.
Twitter's co-founder and executive chairman Jack Dorsey is due to moderate that Wednesday session at the White House.
Fox.com, another Fox Entertainment Group website, was the target of an attack by hacker group Lulz Security in May.
LulzSec has also made assaults on Sony, the U.S. Central Intelligence Agency (CIA) and other targets. The attacks have mostly resulted in temporary disruptions to websites and the release of user credentials.