Brahimi, a veteran Algerian diplomat serving as a joint U.N.-Arab League peace envoy for Syria, delivered his assessment to a closed-door meeting of the U.N. Security Council.
Rice said after the briefing that Brahimi was committed to his work despite few signs of a breakthrough on the Syrian crisis.
"Brahimi gave a very frank and grim assessment of the situation, both inside Syria and for the region," said Rice.
She added that there were unresolved issues among members of the Security Council that were preventing the body from moving forward on a resolution.
"There is no obvious way forward," she said.
Permanent Security Council members China and Russia have objected to resolutions that would censure Syria for the ongoing bloodshed, saying they lacked balance.
Brahimi expressed frustration with Syrian President Bashar Assad during an early January interview with the BBC. The Algerian diplomat added that Assad lost an opportunity to bring about "real change" in the country.
Meanwhile, Syrian Opposition Coalition leader and exiled Damascus cleric Ahmad Moaz Khatib was quoted by The Daily Star newspaper in Lebanon as saying he was ready to discuss a political solution with Syrian leaders.
His comments, however, were rejected by the Syrian National Coalition, which said Khatib's personal statement weren't representative of the true opposition.