Attorney General Alberto Gonzales resigned from office on Monday, ending a controversial tenure as chief law enforcement officer that blemished the administration of President George W. Bush.

U.S. officials, who confirmed his departure, said Gonzales was to make a formal statement at the Justice Department at 10:30 EDT. Bush was also expected to make a statement later Monday morning, but a senior administration official said the president had not yet decided on a nominee to replace him.

U.S. Solicitor General Paul Clement will serve as acting attorney general, the official said, amid speculation that Homeland Security Secretary Michael Chertoff could be a candidate for a permanent replacement.

A 51-year-old Bush loyalist, Gonzales was at the center of a political firestorm over the sacking of federal prosecutors last year, which critics in Congress complained were politically motivated, and faced a possible perjury investigation for his testimony before Congress.

Gonzales spoke to Bush by telephone on Friday and then visited him on Sunday at his Crawford ranch, where he formally submitted his letter of resignation, said another senior administration official.

He (Bush) very reluctantly accepted it, the official said. Asked whether anyone from the White House had suggested that Gonzales resign, the official said: It was his decision.

Reaction from Democrats was swift.

Sen. Patrick Leahy of Vermont, chairman of the Senate Judiciary Committee, blamed Gonzales and Bush for a severe crisis of leadership at the Justice Department.

I hope the attorney general's decision will be a step toward getting to the truth about the level of political influence this White House wields over the Department of Justice and toward reconstituting its leadership, he said in a statement.

Senate Majority Leader Harry Reid of Nevada said: This resignation is not the end of the story. Congress must get to the bottom of this mess and follow the facts where they lead, into the White House.

Gonzales is the latest member of Bush's inner circle to leave the White House as the administration heads toward the final year of its two-term reign. Top Bush adviser Karl Rove departed last week, following former communications director Dan Bartlett earlier this year.

Gonzales worked for Bush when he was governor of Texas in the 1990s. He served as White House lawyer in Bush's first term as president before becoming the first Hispanic attorney general in February 2005.

Current and former administration officials had said the department's integrity had been damaged under Gonzales with controversy over the firing of the prosecutors, his support for Bush's warrantless domestic spying program adopted after the September 11 attacks and other issues.

EMPLOYEE MORALE

They said as a result employee morale had been hurt and Gonzales' relations with the Democratic-controlled Congress had deteriorated beyond repair in a firestorm of criticism from lawmakers, including some Republicans.

Republican Sen. Arlen Specter of Pennsylvania told Gonzales earlier this year, the Justice Department was dysfunctional. But Gonzales told Congress, I have decided to stay and fix the problems.

While acknowledging mistakes in the handling of the dismissals, Gonzales had denied the firings were politically motivated to influence federal probes involving Democratic or Republican lawmakers.

Gonzales also came under fire after his deputy James Comey testified before Congress that while at the White House Gonzales attempted to pressure critically ill John Ashcroft, then-attorney general, to accept the domestic surveillance program.

Only in January, in an abrupt reversal, Gonzales said the domestic-spying program finally would be subject to court approval.

Gonzales also drew fire from civil liberties groups for writing in January 2002 that parts of the half-century-old Geneva Convention on the treatment of prisoners of war were obsolete and some provisions were quaint.

Bush has defended Gonzales and cited Gonzales' rise as an achievement for Hispanics, the largest minority in the United States.

I haven't seen Congress say he's done anything wrong, Bush said at a recent news conference. As a matter of fact, I believe we're watching ... a political exercise.

(Additional reporting by Deborah Charles, James Vicini and Tabassum Zakaria in Washington and Jeremy Pelofsky in Crawford, Texas)

George W. Bush