WASHINGTON — Susan Rice, the embattled U.N. ambassador, abruptly withdrew from consideration to be the next secretary of state on Thursday after an ugly standoff with Republican senators who declared they would vigorously oppose her nomination.

The move elevates Massachusetts Sen. John Kerry as the likely choice to be the nation’s next top diplomat when Hillary Rodham Clinton departs soon.

President Barack Obama accepted Rice’s decision with a shot at Republicans.

“While I deeply regret the unfair and misleading attacks on Susan Rice in recent weeks, her decision demonstrates the strength of her character,” he said.

Rice had become the public face of the tangled administration description of what happened in Benghazi, Libya, on Sept. 11 of this year when four Americans, including the U.S. ambassador to Libya, were killed in what is now known to have been a terrorist attack.

Rice withdrew her name in a letter to the president, saying she was convinced the confirmation process would be “lengthy, disruptive and costly — to you and to our most pressing national and international priorities.”

“That trade-off is simply not worth it to our country,” Rice said.