NEW YORK – The Associated Press, one of the world’s largest news agencies, said Tuesday that a computer hacking attack caused it to send out an erroneous Twitter post.

The false information about explosions at the White House and President Obama being injured came after repeated attempts by hackers to gain access to AP reporters’ passwords, the news agency said in a report. It said it had suspended its account and would work to fix the vulnerability.

The Dow Jones Industrial Average and the Standard & Poor’s 500 Index each fell about 1 percent before rebounding. A separate Twitter account operated by the AP’s corporate communications team followed up minutes later with its own message: “That is a bogus @AP tweet.”

The news agency is the latest victim in a series of hacking cases against news outlets, including the New York Times and the Wall Street Journal.

The false tweet spotlights the increasingly close ties between social media and financial markets. The AP’s main Twitter account, @AP, had over 1.9 million followers before the hacking.

The incident shows the risk of social media, said Cathy Baron Tamraz, chief executive officer of Berkshire Hathaway’s Business Wire, who called it an “object lesson” in why social media isn’t a substitute for press releases.

“I’ve got over 100 technologists in my shop,” said Tamraz, whose company distributes news releases for corporate clients. “What they spend their time doing is figuring out what the bad guys want to do and preventing them from doing it. That’s the kind of thing I don’t think these social sites were even set up to do. That’s not their core competency.”

“The president is fine, I was just with him,” White House spokesman Jay Carney told reporters minutes after the hacking was discovered.

Twitter accounts are vulnerable to hacking partly because the service lacks a more sophisticated authentication system, according to Wade Williamson, a senior security analyst with Palo Alto Networks Inc.

“The attack does not appear to be particularly technically sophisticated and is likely an example of a traditional account hijacking in which a hacker stole the AP account administrator’s password,” he said in an interview.