U.S. ambassador to the United Nations Nikki Haley, in a statement, denounced how Israel was the only country that is a permanent fixture on the 47-member body's calendar.
"It is not Syria, where the regime has systematically slaughtered and tortured its own people," she said. "It is not Iran, where public hangings are a regular occurrence. It is not North Korea, where the regime uses forced labor camps to crush its people into submission. It is Israel, the only democracy in the Middle East."
The boycott announced by the State Department comes as the Trump administration contemplates ending U.S. participation at the council. A letter from U.S. Secretary of State Rex Tillerson to advocacy groups, obtained by The Associated Press last week, said the U.S. wouldn't continue participating unless the council undergoes "considerable reform."
"Today's actions in the council are yet another reminder of that body's long-standing bias against Israel," State Department spokesman Mark Toner said in a statement. "No other nation has an entire agenda item dedicated to it at the council. The continued existence of this agenda item is among the largest threats to the credibility of the council."
In New York, U.N. deputy spokesman Farhan Haq, defended the "important" work of the council.
"Obviously, different member states have their opinions about different topics before the council to which they're entitled, but at the same time we do hope that the overall work of the council will be supported by all members," he said, when asked about the U.S. boycott.
In the more than 230 country-specific resolutions at the council since it was founded 11 years ago, more than a quarter of them have been focused on Israel, whose policies in Palestinian areas have raised rights concerns for decades. Israel easily tops the rankings: second-place Syria, where since 2011 hundreds of thousands have been killed, has been the subject of 19 resolutions.
Earlier Monday, the U.N.'s special rapporteur on "rights in the Palestinian territories occupied by Israel," Michael Lynk, decried how "illegal settlement enterprise has moved at an alarming pace" this year.
Lynk pointed to announcements by Israel to build 6,000 new housing units in Palestinian areas, accompanied by "high rates of demolition of Palestinian homes in the West Bank, including East Jerusalem." He also cited a U.N. Security Council resolution in December that called the establishment of settlements in the West Bank a "flagrant violation" of international law.
Edith M. Lederer at the United Nations contributed to this report.