Video: Sen. Johnson's Fiery Exchange with Sec. Clinton | News

WASHINGTON (AP) - Secretary of State Hillary Rodham Clinton says her department is moving swiftly and aggressively to strengthen security at U.S. missions worldwide, after the deadly September raid on the U.S. consulate in Libya.

In what is probably her last appearance on Capitol Hill as the nation's top diplomat, Clinton again took responsibility for the department's missteps leading up to the assault at the consulate in Benghazi that killed Ambassador Chris Stevens and three other Americans.

Her voice cracked at times as she spoke of seeing the caskets of the Americans return to the United States, and comforting family members of the victims.

There was a testy exchange with one GOP senator. She'd been pressed by Sen. Ron Johnson of Wisconsin about the initial account of the Libya attack from Susan Rice, the U.S. ambassador to the U.N., who said the attack stemmed from a protest over a video. Clinton today challenged the GOP focus on those comments, asking, "What difference does it make?" She says she's focused on improving security, rather than on revisiting the "talking points" used by Rice.

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