WASHINGTON —  The FBI said Friday there is no specific, credible threat of a terror attack aimed at college basketball arenas or other sports stadiums, but acknowledged alerting law enforcement to a recent Internet posting discussing such attacks.

The FBI and Homeland Security Department distributed an intelligence bulletin Friday to state and local law enforcement nationwide describing the online threat against sporting venues, said Special Agent Richard Kolko, an FBI spokesman in Washington.

"We have absolutely no credible intelligence or threats pertaining to this issue," Kolko said.

With conference tournaments taking place this weekend, and the NCAA tournament scheduled to begin next week, the bulletin was sent "out of an abundance of caution," Kolko said.

"We have been in touch with Homeland Security and the FBI about this issue," said NCAA spokesman Erik Christiansen.

"We do not believe there is an imminent threat," he said. "We are in constant communication with the local, state and federal law enforcement agencies, including Homeland Security and the FBI. This is not new; we are in regular contact with all these law enforcement agencies at every level."

The online message described a potential attack in some detail, calling it an efficient way to kill thousands of people using homicide bombers armed with explosives hidden beneath their winter clothing, said a federal law enforcement official who read the bulletin.

But the government document also said U.S. intelligence sources could not corroborate the information or say whether the site was linked to Al Qaeda.

Christiansen said, "There was no mention of a specific event or organization."

In the past, intelligence assessments have been sent in advance of major holidays and sporting events because they pose an inviting target for terrorists.