The Associated Press has confirmed a tweet about explosions in the White House was posted yesterday afternoon after its official Twitter account was hacked.

Just after 6pm UK time, the news agency’s twitter account posted “Breaking: Two Explosions in the White House and Barack Obama is injured”. It was sent to AP’s near-one million followers and retweeted over 1,000 times.

White House press secretary Jay Carney confirmed the president’s safety in a press conference to the media. “The President is fine, I was just with him,” he said.

AP said it suspended both the compromised Twitter account and its AP Mobile account after they were targeted by phishing attacks on its corporate network.

FBI spokeswoman Jenny Shearer confirmed to the news agency that the law enforcement agency had opened an investigation, but declined to comment further.

The false tweet caused share prices in US markets to drop, which was indicated by the Dow Jones industrial average dropping 150 points.

According to AP, a group calling itself the Syrian Electronic Army claimed responsibility for the attack, though the claim is yet to be verified.

AP is the latest media organisation to fall victim to hackers following several high-profile incidents over the past month.

On Monday, US broadcaster CBS news reported that fake tweets criticising support for terrorist rebels in Syria were sent from its @60Minutes and @48Hours Twitter accounts, the BBC reported.

The New York Times, The Wall Street Journal and The Washington Post have also been hacked in recent months.

In February, Twitter itself was hacked in an attack by what it described as “extremely sophisticated” hackers. The micro-blogging platform’s investigation found that hackers may have accessed user information, including usernames and email addresses, of around 250,000 users.