FBI chief sees no imminent threat from Zazi case

WASHINGTON (Reuters) - FBI Director Robert Mueller on Wednesday said there was no imminent threat related to the case of an Afghan-born man charged with plotting a bombing attack in the United States.

Najibullah Zazi, indicted by a grand jury on a charge of conspiracy to use weapons of mass destruction, pleaded not guilty on Tuesday and was ordered held in prison without bail.

"We do not believe there is an imminent threat," Mueller said at a Senate Homeland Security Committee hearing. The investigation was continuing, he said.

Prosecutors allege Zazi took a bomb-making course at an al Qaeda training camp in Pakistan, had bomb-making notes on his laptop computer, and acquired bomb-making materials similar to those used in the 2005 London attacks, buying acetone and hydrogen peroxide at beauty supply stores.

Zazi, an Afghan immigrant, is a permanent U.S. resident.

Department of Homeland Security Secretary Janet Napolitano told senators that U.S. officials had considered raising the national threat level because of the Zazi investigation, but decided against it.

The current threat level for the country is set at "elevated," or yellow, while it is considered "high," or orange, for all domestic and international flights.

"We thought about it and rejected it because we didn't have in the Zazi investigation any kind of specific location, time, threat that would, in our view, justify actually raising the color codes," Napolitano told the committee.

The highest level in the five-tier system is "severe," or red, though DHS is considering recommendations to change the system amid some criticism that it is not very effective.

(Reporting by Tabassum Zakaria and Jeremy Pelofsky, editing by Will Dunham)