Mueller testified before the Judiciary Committee, which is considering a bill allowing the extension. Mueller's 10-year term ends this summer, but President Obama wants him to remain in the position until 2013.
While Mueller in his prepared remarks did not directly push for the extension, he suggested the FBI needs an experienced hand in charge.
"The FBI has never faced a more complex threat environment than it does today," he said. "Over the past year, we have seen an extraordinary array of national security and criminal threats, from terrorism and espionage to cyberattacks and traditional crimes."
He said intelligence gathered during the May raid on Osama bin Laden's Pakistan compound showed al-Qaida is committed to launching attacks in the United States. At the same time, he said, the country is under threat on its southern border because of drug violence in Mexico.
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