General John Abizaid, the top US commander in the Middle East, on Wednesday warned that a phased withdrawal of US troops within six months, which some Democrats want, would increase sectarian violence in Iraq.

Gen Abizaid also drew the ire of John McCain, the Arizona senator and Republican frontrunner for the 2008 presidential race, by saying he did not believe more troops would help the US stop the bloodshed in the war-torn country.