The United Nations' top human rights official, a lightning rod for denunciations from many countries stung by her criticism, said Friday that she is quitting after only one term.

High Commissioner for Human Rights Louise Arbour said she told U.N. Secretary-General Ban Ki-moon that she will be unavailable for a second term in the job after her four years in office end on June 30.

Arbour, who won international acclaim for indicting former Yugoslav President Slobodan Milosevic in 1999 when she was chief prosecutor in The Hague, did not tell the 47-nation U.N. Human Rights Council why she is stepping down.

But she told a small group of reporters that she wanted to spend time with her family after constant travel and long hours. She acknowledged that she found much of the criticism hurtful, but she said she was not quitting because of it.

"On the contrary, I have to resist the temptation to stay to confront it," the 61-year-old former Canadian supreme court justice said.

Arbour is the second high-ranking U.N. official this week to announce plans to step down. On uThursday, peacekeeping chief Jean-Marie Guehenno of France disclosed he would end eight years on the job this summer.

After her speech, Arbour scolded some council members for going too far in criticizing her and her staff by impeaching their integrity or alleging "bias, hypocrisy, insubordination or dereliction of duty" as being "outside the acceptable range."

On Monday, Zimbabwean Justice Minister Patrick Anthony Chinamasa told the council that his country "joins others in voicing its discontent with the office of the High Commissioner on Human Rights for repeated dereliction of duty."

Arbour last year denounced police violence against opposition party members in Zimbabwe as "shocking."

She has criticized China's use of the death penalty and said the so-called U.S. war on terror was eroding the worldwide ban on torture, noting reports of secret U.S. detention centers.

John Bolton, the U.S. ambassador to the U.N. at the time, said it was "inappropriate and illegitimate for an international civil servant to second-guess the conduct that we're engaged in the war on terror, with nothing more as evidence than what she reads in the newspapers."

The U.S. Mission to U.N. offices in Geneva on Friday released a statement acknowledging differences but crediting Arbour's dedication.

"Although no country, including the U.S., has agreed with the high commissioner on every issue, we respect her dedication to the cause of promoting and protecting human rights," the statement said.

A recent mistake by her office inflamed anger among pro-Israel groups. While the office later clarified that Arbour did not endorse a provision in an Arab human rights charter equating Zionism with racism, her original support for the document led to a fury of reaction among pro-Israel Web sites, with some blog entries calling for her death.

Arbour, however, has been well-regarded by human rights organizations.

"The criticism she receives is a tribute to the good work that she's been doing," said Amnesty International spokesman Peter Splinter.

"She's been unflinching in challenging human rights violations in big and powerful countries as well as in countries not so big and not so powerful," Splinter said. "It's going to be a real challenge for the secretary-general to replace her."