Universal Studios: Affected by the attacks
Cheryl Mimura, a spokeswoman for the FBI told Variety, the trade newspaper: "The FBI provided a threat advisory to the movie studios in Los Angeles.
"The uncorroborated threat states that a film studio in California could be the target of a terrorist attack in retaliation for any possible bombing attacks by the United States in Afghanistan. It seems to be a credible threat.''
Hollywood studios have vowed to increase their security as word spread of an unspecified terrorist threat against them.
Daily Variety said it obtained memos from sources at five studios, all detailing new security measures.
The studios were Fox Entertainment Group Inc's 20th Century Fox, Sony Corp's Sony Pictures Entertainment, Walt Disney Co, Vivendi Universal's Universal Pictures and AOL Time Warner Inc's Warner Bros, it said.
Metro-Goldwyn-Mayer Inc planned to notify employees of new security measures on Friday, the paper said.
Television networks and talent agencies throughout Hollywood have received similar messages.
Tours halted
Reaction was swift across Hollywood.
On Thursday studio entrances were shut down, barricades were ordered and set in place and many studio tours were abruptly halted.
Under the new security orders, most studios will have only one point of entry with increased security guards.
Most film studios and other businesses in Hollywood were open as normal on Friday although CBS was briefly closed "for security purposes".
Despite the scares, an FBI spokesman in Washington said the studios may have overreacted.
He said the agency did meet with studio representatives but did not discuss anything "specific" in terms of threats.
Attacks
"There wasn't anything that came from this press office or the FBI that said, 'Hey, you guys better be prepared for something.' It's more of a 'be aware' notification. [But] people might have taken it for something more than that."
The film community in Hollywood was sent reeling, like the rest of the US after last Tuesday's attacks.
And there is a sense that Hollywood will never be the same again.