The Secret Service said Monday it will investigate the hacking of Fox's political Twitter account over updates claiming that President Barack Obama had been assassinated.

Hackers broke into the Fox News Politics account early Monday, leaving a series of six tweets reporting that Obama had been shot to death in Iowa by an unknown gunman.

In a statement posted on its Web site, Fox News called the tweets "malicious" and "false."

The president celebrated the July 4 holiday at the White House.