US Attorney General Alberto Gonzales resigned yesterday under pressure after months of controversy and political turmoil that President George W Bush angrily blamed on his administration's critics in Congress.Bush, who supported Gonzales during repeated confrontations with the Democratic-controlled Congress, said Gonzales had endured "months of unfair treatment that has created a harmful distraction at the Justice Department."

"It's sad that we live in a time when a talented and honourable person like Alberto Gonzales is impeded from doing important work because his good name was dragged through the mud for political reasons," Bush said in Texas.

Both Republicans and Democrats in Congress had demanded the 52-year-old Gonzales' resignation over the sacking of federal prosecutors last year, which critics said were politically motivated.

He faced a possible perjury investigation for testimony before Congress, where legislators complained that his leadership had rendered the Justice Department dysfunctional.

Gonzales also weathered criticism on several other fronts, including his support for Bush's domestic spying programme and his 2002 legal opinion that parts of the Geneva Convention on the treatment of prisoners of war were "obsolete."

He announced at the Justice Department that his resignation would take effect on September 17. But the attorney general refused to give any reason for his sudden decision to leave.

"I have lived the American dream," said Gonzales, a son of migrant workers who began working for Bush as an attorney when the president was still the governor of Texas.

"Even my worst days as attorney general have been better than my father's best days," he said.

US Solicitor General Paul Clement will serve as acting attorney general.

As solicitor general, Clement holds the fourth-ranking position at the Justice Department. He was asked by Bush to head the agency until a new attorney general is nominated, then confirmed by the Senate.

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.

PHOTO CAPTION

Attorney General Alberto Gonzales pauses while announcing his resignation at the Department of Justice in Washington, Monday, Aug. 27, 2007. (AP)