US diplomat Susan Rice has admitted releasing incorrect information after September's attack on the American consulate in Libya.
Republican Party senators are expected to try to block the bid by Ms Rice, who is the American ambassador to the United Nations, to become the country's next Secretary of State.
Ms Rice has failed to shut down criticism over what the administration knew about the fatal attack on a US consulate in Libya in September.
She said there had been no attempt to mislead the public, but Republicans were unconvinced.
Ms Rice has admitted she wrongly said the assault arose out of a spontaneous protest.
The BBC reports the 11 September assault on the US consulate triggered a major political row over who knew what and when.
Days afterwards, Ms Rice said in a series of TV interviews that it seemed to have developed out of protests over an anti-Islamic film.
Later intelligence reports suggested it was possibly tied to al-Qaeda affiliates.
The attack left four Americans dead, including Ambassador Christopher Stevens.
Senator Lindsey Graham said he still has reservations about Ms Rice's original explanation describing it as "a statement disconnected from reality".
Sen Graham said that he was "more disturbed now than I was before", adding that he would "absolutely" attempt to block any nomination of Ms Rice for Secretary of State.
Senator John McCain said: "We are significantly troubled by many of the answers that we got and some that we didn't get concerning evidence that was leading up to the attack."
White House press secretary Jay Carney said on Tuesday there were "no unanswered questions" about Ms Rice's response to the Benghazi incident, accusing Republicans of being obsessed with it.
The current Secretary of State, Hillary Clinton, is stepping down in January.