The Obama administration said Wednesday it will boycott a world conference against racism being held at U.N. headquarters in September because of concerns about anti-Semitism.

The U.N. summit marks the 10-year commemoration of the 2001 World Conference Against Racism that was held in the South African city of Durban. The U.S. and Israel walked out of that meeting over a draft resolution that criticized Israel and equated Zionism with racism.

The United States will not participate in the upcoming conference because the Durban process "included ugly displays of intolerance and anti-Semitism," Joseph E. Macmanus, acting U.S. assistant secretary of state for legislative affairs, wrote in a letter to Democratic Sen. Kirsten Gillibrand.

AP obtained a copy of the letter, sent Wednesday to Gillibrand and other members of Congress.

Gillibrand welcomed the administration's decision. "It is an insult to America that the United Nations has decided to hold the Durban III conference in New York just days from the tenth anniversary of the September 11th attacks," the New York senator said in a release Wednesday.

"We all witnessed how extreme anti-Semitic and anti-American voices took over" the original gathering in South Africa and a follow up conference, the senator wrote.

The administration's move was also lauded by the Conference of Presidents of Major American Jewish Organizations, an umbrella of 52 groups including B'nai B'rith International, the Anti-Defamation League, the American Jewish Committee and Hadassah, the Women's Zionist Organization of America.

There was no immediate response to a request sent late Wednesday afternoon seeking comment from the New York office of the U.N. High Commissioner for Human Rights.

Macmanus' letter was responding to a letter Gillibrand had sent America's U.N. Ambassador Susan Rice asking her to "send a strong signal" by not participating. She also applauded Canada's earlier decision to boycott the event.

"In December, we voted against the resolution establishing this event because the Durban process included ugly displays of intolerance and anti-Semitism, and we did not want to see that commemorated," Macmanus told the senator.

He added that in 2009 the U.S. withdrew from the planning of the conference because it reaffirmed the 2001 Durban Declaration, "which unfairly singled out Israel and included language inconsistent with U.S. traditions of robust free speech."

The U.S. and at least seven other countries also boycotted a 2009 follow up event that the U.N. held in Geneva, citing concerns that Islamic countries would demand a denunciation of Israel and insist that all criticism of Islam be banned.

As for this year's event, "the United States delegation in New York has not been involved in the formal negotiations on the modalities resolution or the outcome document and has had a notetaker only in these proceedings," the State Department letter said. "We share your concern about the Durban commemoration's timing and venue as just days earlier, we will have held solemn ten-year memorials for those murdered in the September 11 terrorist attacks."

The letter said that the United States is "fully committed to upholding the human rights of all people and to combating racial discrimination, xenophobia, intolerance, and bigotry."