A top Republican lawmaker demanded Friday that US Ambassador to the United Nations Susan Rice resign, charging she misled Americans over the assault on the US consulate in Benghazi.

Congressman Peter King's intervention was the latest effort by Republicans to make the White House pay a political price over the fallout from the attack, which killed US envoy to Libya Christopher Stevens and three other Americans.

"I think Susan Rice should resign. She is America's foreign policy spokesman to the world as ambassador to the UN," the New York congressman told National Review Online.

King demanded the departure of Rice, a member of President Barack Obama's inner circle, after she appeared on US talk shows in the wake of the September 11 attack and dismissed suggestions it was a planned terrorist action.

"We don't see at this point signs this was a coordinated plan, premeditated attack," Rice said on "Fox News Sunday" on September 16.

"Obviously, we will wait for the results of the (FBI) investigation and we don't want to jump to conclusions before then."

Later Friday, on CNN, King said that Rice had been "irresponsible" to say there was no terrorist involvement in the Benghazi attack and argue instead that it evolved out of protests in the Arab world over an Internet video made on US soil that denigrates Islam and its Prophet Mohammed.

"The presumption should have been leaning toward it being terrorism," said King, chairman of the House Homeland Security Committee.

The White House quickly came to the defense of Rice, seen as a top candidate for the secretary of state post if Obama wins a second term in November.

"Ambassador Rice has done an extraordinary job representing our country at the United Nations and the president is enormously grateful to her for her service," said National Security Council spokesman Tommy Vietor.

"He looks forward to her continued service."

Vietor also said that Rice was not offering a personal opinion on Sunday shows after the attack, but representing the views of the US government, based on the best assessments of US intelligence agencies at the time.

"You've seen the intelligence community say that in the immediate aftermath of the attacks, there was information that led them to assess that the attack began spontaneously following protests earlier that day at our embassy in Cairo," Vietor said.

"As we learned more information, we updated our information."

The story of the Benghazi attack as told by the Obama administration has evolved over the last two weeks, with officials at first declining to term the assault a terrorist action.

On Friday, the Office of the Director of National Intelligence said that the consulate attack was planned and linked to Al-Qaeda, but stressed it was unclear if known terror leaders had exerted overall command and control of the operation.

Both Defense Secretary Leon Panetta and Secretary of State Hillary Clinton have called the assault a "terrorist attack," with the Pentagon chief also suggesting that it took days for the US government to conclude extremists had launched an orchestrated assault.

Clinton had first termed the assault a "terrorist attack" on September 21. Obama indirectly referred to the assault as terrorism in his initial remarks on the killing of Stevens on September 12, when he said Americans would not be shaken by "acts of terror."