Hackers spooked markets Tuesday after breaking into the Associated Press's Twitter account and falsely reporting President Barack Obama had been injured after two blasts at the White House.
A brief alert on the news agency's @AP account read: "Breaking: Two explosions in the White House and Barack Obama is injured."
Almost immediately the wire service posted via its corporate communications feed that its @AP Twitter account had been hacked, before promptly suspending the service.
"Advisory: @AP Twitter account has been hacked. Tweet about an attack at the White House is false. We will advise more as soon as possible," @AP_CorpComm posted.
White House spokesman Jay Carney later told reporters the president was unharmed.
"I can say that the president is fine," Carney said shortly after the fake tweet. "I was just with him."
Stock markets plunged just as the report came out, with the Dow Jones Industrial Average losing 130 points, or 0.9 percent, and the S&P 500 dropping 12 points, or 0.8 percent.
Just as quickly they rebounded to where they were before the tweet, all within three or four minutes.
Hackers regularly target the Twitter accounts of news organizations, with online activists backing the regime of Syrian President Bashar al-Assad claiming responsibility for hacking an AFP Twitter account in February.
The so-called Syrian Electronic Army, which said it had hacked the AFP account, had earlier claimed credit for hacking the websites of Sky News Arabia and Al-Jazeera Mobile.
On Saturday, social media accounts connected to CBS News programs "60 Minutes" and "48 Hours" were also targeted.
A tweet on the @60Minutes Twitter account stated: "Exclusive: Terror is striking the #USA and #Obama is shamelessly in bed with Al-Qaeda."
The post was later deleted while CBS News stated: "We have experienced problems on Twitter accounts of @60Minutes & @48Hours; We apologize for the inconvenience; Twitter is resolving issues."
Explore further: AFP's Twitter photo account hacked