The website and Twitter feed of the Financial Times were hacked on Friday, apparently by the "Syrian Electronic Army," a group of online activists who say they support Syrian President Bashar al-Assad.
The group posted links on the newspaper's Twitter feed to a YouTube video, uploaded on Wednesday, which purports to show members of the al-Qaida-linked Nusra Front Syrian rebel group executing blindfolded and kneeling members of the Syrian army.
The video could not be independently verified.
Hacking attacks on verified Twitter accounts of media organizations have triggered urgent calls for the micro-blogging website to increase account security, particularly for news outlets.
"Various FT blogs and social media accounts have been compromised by hackers and we are working to resolve the issue as quickly as possible," a statement from the FT press office said. The paper is owned by Pearson Plc
Twitter was not immediately available for comment.
Stories on the FT's website had their headlines replaced by "Hacked By Syrian Electronic Army" and messages on its Twitter feed read: "Do you want to know the reality of the Syrian 'Rebels?'", followed by a link to the video.
Robbed: Secret ‘Financial War’ Will Wipe Out Your Wealth, Warns Pentagon Adviser
The FT is the latest media organization under attack by the group, which was also behind last month's incident involving the Associated Press.
In that hack, the Syrian Electronic Army took control of AP's official Twitter feed and sent out a bogus message that two explosions at the While House injured President Barack Obama.
The false tweet triggered the U.S. financial markets to take a brief but steep plunge.
"Twitter has become a big enough media outlet that they should provide better security for high-value accounts like the Associated Press, the FT and others," said Mikko Hypponen, chief research officer with security software maker F-Secure.
Indeed since the spate of attacks commandeering media organizations' Twitter accounts, including the BBC, National Public Radio, CBS, Reuters News, and French news service France 24, the pressure for the social media site to tighten up security will only intensify.
Twitter has 200 million users world-wide who send out more than 400 million tweets a day, making it a potent distributor of news.
For years, security experts have called on Twitter to introduce an additional safety measure, a two-step process to log in, that would help reduce breaches.
This type of authentication has long been used by governments and big corporations and in recent years some consumer Internet companies like Facebook, Google, and Microsoft have embraced it.
"You can get two-factor authentication for World of Warcraft, but you can't get it for Twitter. Go figure," Hypponen said.
© 2015 Thomson/Reuters. All rights reserved.