The announcement by the president, Mahmoud Abbas, in a televised speech delivered at his headquarters in Ramallah in the Israeli-occupied West Bank, was the first time he has formally committed to such a strategy, which Palestinian officials have been moving toward for months as their frustration over stalled peace talks with Israel has intensified. American, Israeli and European diplomats have struggled to dissuade Mr. Abbas and his aides from taking such a step.

“We need to have full membership at the U.N.,” Mr. Abbas said in the speech, which was broadcast live on Al Jazeera and other outlets. “We need a state, a seat at the United Nations and nothing more.”