Timoney, 61, once dubbed "America's Best Cop" by Esquire magazine, said he had fulfilled his mission by reducing crime and lowered officer-involved shootings.

Miami's new mayor, Tomas Regalado, said yesterday that he had instructed the city manager to ask Timoney to step down, saying crime was rising and officer morale was low.

"We are very happy that we are past the chief-of-police issue," Regalado said.

The Miami Herald cited city officials as saying that a new chief would be named next week but that Timoney would remain with the city through the end of the year to help with the transition.

Timoney served in Philadelphia from 1998 through 2001. Before that, he rose through the ranks of the New York Police Department, eventually becoming second-in-command.

'Very proud'

WFOR-TV (CBS4) in Miami reported online last night that Timoney had tendered a "letter of retirement" in which he said he was "very proud to have served this great department, this city and its citizens." The Herald said his letter gave no indication of what Timoney might do next.

Timoney was born in Dublin and raised in the Bronx. His tenure in Miami began in 2003 as 11 police officers went to trial on federal charges of fabricating evidence and planting guns at crime scenes. His task was to clean up the department, especially officer-involved shootings.

Under Timoney, the police department dramatically lowered officer-involved shootings, at one point going 18 months without an incident.

'A different tone'

But Timoney's record on civil liberties was questioned in November 2003. During protests at the Free Trade Area of the Americas conference, 146 people were arrested and at least seven lawsuits were filed against the city.

Protesters said officers had overreacted, using rubber bullets, batons, tear gas, and concussion grenades against them. Timoney called his crowd-control tactics "the Miami Model" and said had he wanted to avoid the mayhem seen during similar anti-trade protests in Seattle.

Timoney also rankled some in 2007, when it was discovered that he drove - yet failed to disclose receipt of - a Lexus SUV from a local auto dealer.