The remarks, which included warnings of the increasingly volatile Middle East, follow renewed warnings by Moqtada al-Sadr that he would reactivate his militia if US forces extend their stay.
A senior US military official said Wednesday that keeping some US forces in the country would be "best for Iraq" and warned that the Iraqi military was not equipped to ward off threats in an increasingly volatile region.
The remarks, made on condition of anonymity due to the political sensitivity of the issue, indicate a growing concern by American officials that the Iraqi government is closing the door on a new agreement for US troops in Iraq past the end of this year.
The comments to a small group of reporters also signaled a concern that a militarily weak Iraq could be another destabilizing factor in what has become a volatile region.
The remarks, the most pointed yet by a senior military official after months of silence, follow renewed warnings by Shiite cleric Moqtada al-Sadr that he would reactivate his Mahdi Army militia if US forces or even a significant embassy presence remains.