The Moscone Center notified the San Francisco Police Department of a bomb threat that targeted the center at 1:20 p.m. PDT, said Isabel Crowell, an SFPD spokeswoman. The center said it had received multiple threatening calls. About two dozen police officers arrived at the center, and Oracle ordered the evacuation of the building shortly afterwards.
The police said they found no bombs after hours of searching and began allowing people back into the center at about 4:00 p.m. Oracle told the SFPD that as many as 11,000 people were at the conference, according to one officer.
No one had yet claimed responsibility for the threat, according to police. The Moscone Center, the SFPD and a Bay Area FBI office all received threatening calls about it, Sgt. Neville Gittens with the SFPD said.
The threat falls on the eve of the second anniversary of the Sept. 11 terrorist attacks.
"Especially with the anniversary of 9/11 tomorrow, we kind of expected these things to happen," Crowell said.
An Oracle representative said the bomb threat was made against the Moscone Center, not Oracle. The Moscone Center has been the target of several bomb threats before, police Capt. Dennis Martel said.
Conference attendees started evacuating both the north and south halls of the Moscone Center following an announcement over an intercom that asked people to calmly exit due to "a security issue." Thousands of people filled the sidewalks in front of the convention center at approximately 3 p.m. A helicopter circled the area, and police brought in bomb-sniffing dogs.
"I'd rather be safe out here than sorry," said conference attendee Claudia Arguello, a database administrator manager at Bechtel, who was standing on sidewalk in front of the building.
OracleWorld, which began Monday and is scheduled to conclude Thursday, is the annual customer conference of the world's second-largest software company. Oracle, based in Redwood Shores, Calif., said it will resume the conference Thursday morning, cutting short the rest of Wednesday's agenda.CNET News.com's Ben Charny contributed to this report.