WASHINGTON — The United States will not participate in the United Nations-sponsored Durban III conference this September, the State Department said.

In a letter to Sen. Kirsten Gillibrand (D-N.Y.), Joseph Macmanus, acting assistant secretary of state for legislative affairs, confirmed that the United States would not attend the conference, which in its previous iterations has been a forum for anti-Semitism and anti-Israel rhetoric. JTA obtained a copy of the letter.

In November, the United States voted against a U.N. resolution to establish the conference. The following month, Gillibrand led a coalition of 18 senators in signing a letter to the American ambassador to the U.N., Susan Rice, urging the U.S. not to participate in the conference, scheduled for Sept. 21 in New York.

The Durban III conference is meant to mark the 10-year anniversary of the U.N.’s World Conference Against Racism in Durban, South Africa, during which the delegations from the United States and Israel walked out in protest as the tenor turned increasingly anti-Israel and anti-Semitic.

“The United States will not participate in the Durban Commemoration,” Macmanus wrote in the letter. “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.”

Gillibrand applauded the decision in a statement Wednesday.

“I commend the Obama Administration decision to withdraw from this event,” Gillibrand said. “We all witnessed how extreme anti-Semitic and anti-American voices took over Durban I and Durban II, and we should expect the same thing to happen with Durban III.”

The U.S. and Israel, along with seven other countries, boycotted Durban II in 2009, during which Iranian President Mahmoud Ahmadinejad delivered a keynote speech assailing Zionism.

In November, Canada was the first country to announce it would not participate in Durban III. Israel announced the following month that it would boycott the conference.