He added that failure "could also deepen broader Shi'a-Sunni fissures that are already apparent throughout the region."
General John Abizaid was testifying before U.S. senators in the first testimony on Capitol Hill by a senior military figure since American voters, angered by Iraq, stripped President George W. Bush's Republicans of majorities in both chambers of Congress.
Abizaid said he did not believe that sending more U.S. troops to Iraq is "the solution to the problem."
Talking about violence, Abizaid said sectarian violence is still "unacceptably high" but had lessened since August, when he said that sectarian violence was worse than ever and could lead Iraq toward "civil war."
(Reuters, AFP, AP)