Newsweek's Twitter account was apparently hacked on February 10, posting threatening messages toward U.S. President Barack Obama's family and in support of the militant group Islamic State (IS).
The group, which identified itself with the hashtag #CyberCaliphate, said it was "watching" Obama and his family and wished them a "Bloody Valentine's Day."
The same group claimed responsibility for a hack to the Twitter account of United States Central Command on January 12.
The group also tweeted what it said were "leaked" documents from the Pentagon on the Newsweek account, which has 2.51 million followers.
The group's tweets were deleted in approximately 20 minutes.