Twitter has suspended the Associated Press's account after hackers sent a tweet from it Tuesday that said, "Breaking: Two Explosions in the White House and Barack Obama is injured."
White House spokesman Jay Carney confirms the president is fine, and AP confirms its account was hacked.
The AP says that the cyber attack "came after hackers made repeated attempts to steal the passwords of AP journalists."
The Syrian Electronic Army has taken responsibility for the hacking.
The group describes itself on its website as "enthusiastic Syrian youths who could not stay passive towards the massive distortion of facts about the recent uprising in Syria." They support the regime of President Bashar Assad.
Last week, NPR.org and NPR's Twitter accounts were hacked by the same group, which also took credit for hacking CBS's website and Twitter accounts over the weekend.
The Dow dropped precipitously, although briefly, following the false news of the explosion. Twitter was integrated into Bloomberg financial terminals earlier this month.
The Syrian Electronic Army's hacktivities go back to at least 2011, when the group focused primarily on defacing Facebook pages and shutting down websites, known as a distributed denial-of-service attack. The group's own Twitter account has been suspended multiple times.