The Twitter accounts for two CBS news programmes in the US have been suspended after being hacked.
Fake messages appearing on the @60Minutes account criticised US support for "terrorist" rebels in Syria and others accused Barack Obama of trying to "take away your guns".
A group calling itself the Syrian Electronic Army claimed to have been responsible for hijacking the accounts.
The @CBSDenver account was also taken over, said news director Tim Wieland.
The SEA group has previously put out messages in support of Syrian President Bashar al-Assad. It appeared to behind the takeover of several BBC Twitter accounts last month and some of NPR's accounts last week.
A CBS spokeswoman confirmed that the accounts had been compromised. CBS said it was working with Twitter to "resolve the issue".
The fake messages that appeared on the @60Minutes account reportedly included:
- "The US government is hiding the real culprit of the Boston bombing"
- "The US government is sponsoring a coup in Venezuela and a terrorist war in Syria"
- "Your duty is to protect your nation from the parasites that have taken your government"
- "Obama wants to destroy the Syrian and American people. We must stop this beast"
Other messages claimed: "Syrian Electronic Army Was Here via @SyrianCyberArmy" and suggested the action was in response to the suspension of the @Official_SEA account.
Tweets sent out on the @48Hours account reportedly included: "General Dempsey calls for #Obama's arrest under new anti-terror laws #48hours".
Gen Martin Dempsey is chairman of the US Joint Chiefs of Staff.
Twitter has not commented on the latest account hackings.