Mueller was appointed by Republican President George W. Bush and began just a week before the Sept. 11 attacks. Well-regarded by Republicans and Democrats, Mueller is known for transforming a crime-fighting agency into the front line of defense against terrorism.
The plan to keep Mueller on is not tied to the U.S. raid in Pakistan that led to the killing of al-Qaeda leader Osama bin Laden this month, or to any threat of retaliation against the United States as a result of that mission, administration officials said.
"Given the ongoing threats facing the United States, as well as the leadership transitions at other agencies . . . I believe continuity and stability at the FBI is critical at this time," Obama said.
Obama will ask Congress for legislation tailored solely for a two-year extension for Mueller. White House officials say that although such an extension has never been granted for an FBI director, it has been done in other term-limited cases and therefore would not set a precedent.
The Republican House Judiciary Committee chairman, Rep. Lamar Smith of Texas, backed Obama's move. "It is important to maintain continuity for our intelligence community during this transition period," Smith said.
The top Republican on the Senate Judiciary Committee, the panel that has jurisdiction over the FBI, offered a cautious but favorable response. "This is an unusual step by the president and is somewhat of a risky precedent to set," said Sen. Charles E. Grassley of Iowa. He called the 10-year term limit on an FBI chief's service, set in 1976, "an important safeguard against improper political influence and abuses of the past."
But he said that "we live in extraordinary times, so I'm open to the president's idea."
The term limit was set in response to the service of J. Edgar Hoover, who died in 1972, ending a decades-long tenure as FBI director that was marred by abuses of power.
Administration officials said they had consulted with lawmakers and were confident an exception would be made to keep Mueller in his job.
Mueller, 66, has told Obama he would stay on for two more years.
