US President Barack Obama said on Thursday that he won't nominate Susan Rice, the current American ambassador to the United Nations, as his next secretary of state.

"Today, I spoke to Ambassador Susan Rice, and accepted her decision to remove her name from consideration for secretary of state," the president said in a statement, bowing to opposition from some Republican senators over possible nomination of Rice to the post.

Rice, long considered a top candidate to be the country's top diplomat when Obama starts his second term in January, has came under scathing attacks by the Republicans over her description of the Sept. 11 attack on the US consulate in Benghazi, Libya, as one arising from a spontaneous protest over an American-made film that denigrated the Prophet Mohammed.

Critics say her remarks downplayed evidence of an obvious terrorist attack just weeks before the Nov. 6 presidential election.

The Obama administration later acknowledged the attack as a terrorist act carried out by militants linked to al-Qaida, in which four Americans were killed including Ambassador Christopher Stevens.

Both Obama and Secretary of State Hillary Clinton have come to the defense of Rice, saying her remarks on major US TV networks five days after the attack were based on information given to every senior administration official at the time.

The row has not faded away after Obama won re-election early last month. Republicans like John McCain and Lindsey Graham, both veteran senators, have vowed to block Rice's nomination as secretary of state.

Rice's meetings face-to-face late last month with some of her critics have failed to blunt the criticism.

"While I deeply regret the unfair and misleading attacks on Susan Rice in recent weeks, her decision demonstrates the strength of her character, and an admirable commitment to rise above the politics of the moment to put our national interests first," Obama said in his statement.

The president heaped praise on Rice, calling her "an extraordinarily capable, patriotic and passionate public servant."

"I am grateful that Susan will continue to serve as our ambassador at the United Nations and a key member of my cabinet and national security team, carrying her work forward on all of these and other issues," Obama said.

Before taking the UN ambassadorial post in 2009, Rice, 48, served on the staff of the White House National Security Council and as assistant secretary of state for African affairs under the Bill Clinton administration.

John Kerry, a senior Democratic senator serving as chairman of the Senate Foreign Relations Committee, is another top contender for the post of secretary of state, as Clinton has said she would leave the post at the start of Obama's second term.