Washington, Jan 24: An angry, combative and sometimes emotional Secretary of State Hillary clashed with Republican critics over her department's handling of the Sep 11 terrorist attack in Libya even as she acknowledged a "systematic breakdown".

"As I have said many times since September 11, I take responsibility," Clinton said Wednesday at two long-anticipated congressional hearings examining the attack that became a major issue in the November presidential election.

Conservative Republicans alleged, as they had during the election campaign, that US Ambassador to UN Susan Rice had misled the nation over the attack at the diplomatic compound in Benghazi in which Ambassador Christopher Stevens and three others were killed.

Rice, they said had provided an erroneous account by suggesting Sunday TV talk shows that the attack grew spontaneously from a protest over an anti-Islam film produced in the US.

"With all due respect, the fact is we had four dead Americans. Was it because of a protest or was it because of guys out for a walk one night decided they'd go kill some Americans," an angry Clinton shot back.

"What difference, at this point, does it make? It is our job to figure out what happened and do everything we can to prevent it from ever happening again," she said.

At both hearings, which together totalled more than five hours, Clinton acknowledged the "systemic breakdown" cited by an Accountability Review Board she appointed.

Clinton said she had accepted all 29 of its recommendations, adding her department was taking additional steps to increase security at US diplomatic facilities around the world.

She also told both the Senate Foreign Relations Committee and House Foreign Affairs Committee that the FBI is pursuing what she called "very positive leads".

But, the 2008 Republican presidential candidate Senator John McCain, one of the harshest critics of the administration over the Benghazi attack, called Clinton's testimony unsatisfactory.

Democrats on both panels praised Clinton's service and noted that House Republicans have voted to cut funding for diplomatic security.

However, Republicans rejected any connection between budget resources and vulnerability at the Benghazi compound, citing a report by a State Department financial officer. (IANS)