By Tabassum Zakaria

WASHINGTON (Reuters) - President Barack Obama told Republican senators on Wednesday that if they had a problem with the handling of the Benghazi attack in Libya, to "go after me" rather than pick on his ambassador to the United Nations, Susan Rice.

Obama's comments, in a combative tone, came after two senior Republican senators said they would block any attempts by the president to put Rice into a Cabinet position that would require Senate confirmation.

Republicans have criticized Rice for going on a round of Sunday talk shows five days after the September 11 attack on the U.S. diplomatic mission in Benghazi and saying that preliminary information suggested it was the result of protests over an anti-Muslim film rather than a premeditated strike.

The White House has said repeatedly the comments were based on the best information Rice had at the time. But Republicans have used her early assessment as a cudgel for criticizing the administration as not being forthcoming about Benghazi, and the senators' remarks on Wednesday suggested they would pursue the issue even though the U.S. presidential election is over.

"But for them to go after the U.N. ambassador who had nothing to do with Benghazi, and was simply making a presentation based on intelligence that she had received, and to besmirch her reputation is outrageous," Obama said.

The U.S. ambassador to Libya and three other Americans were killed in the attack that has raised questions about the security of the diplomatic mission, U.S. intelligence about the threat, and the adequacy of the immediate U.S. response.

The issue has become a sensitive one for the administration after Obama's re-election last week as he shapes his Cabinet for a second term. Rice is considered a possible contender to replace Secretary of State Hillary Clinton, who does not intend to stay, or for another top post.

"We will do whatever's necessary to block the nomination that's within our power as far as Susan Rice is concerned," said Republican Senator John McCain, who was joined by fellow Republican Senator Lindsey Graham.

At his first news conference since being re-elected, Obama retorted: "If Senator McCain and Senator Graham, and others want to go after somebody, they should go after me. And I'm happy to have that discussion with them."

Obama said he had not made decisions on his second-term Cabinet yet, but if he decided that Rice would be the best person to lead the State Department, "then I will nominate her."

Asked why, if Rice had nothing to do with Benghazi she was sent on the talk shows to give the administration's point of view, White House spokesman Tommy Vietor told Reuters: "It made sense to have Ambassador Rice, one of our most senior diplomats, speak about the critical work our diplomats do every day. Ambassador Rice was also uniquely qualified to speak about the broader unrest in the region at the time."

PETRAEUS GOING TO HILL

The Senate and House intelligence committees have scheduled separate closed-door hearings on Thursday about Benghazi. Former CIA Director David Petraeus had initially been scheduled to testify, but after Petraeus' resignation last week over an extramarital affair, acting CIA Director Michael Morell will take his place.

Some senior lawmakers said they still wanted to hear from Petraeus about Benghazi because he had been CIA director at the time of the attack. Continued...