US military commanders say Iraqi forces may be trying to make a last stand in Saddam Hussein's hometown of Tikrit -- the one major Iraqi city still not in US-led coalition hands.
Bands of Iraqi soldiers have been spotted moving toward the city, north of Baghdad.
U-S aircraft have repeatedly bombed Republican Guard positions around Tikrit, and military officials say it is unclear whether the pro-Saddam holdouts can put up a viable defense.
US-led ground forces are less than 100 kilometers away from Tikrit after Iraqi troops abandoned the northern cities of Kirkuk and Mosul. Reports say only a small number of US troops have entered the cities, and that residents have gone on a looting spree.
In western Iraq, US military officials say Iraqis continue to fight in the town of al-Qaim, on the Syrian border. The officials say they suspect the Iraqis may be defending a site containing some kind of banned weapons.
Despite the scattered Iraqi resistance, the White House says Saddam Hussein's regime is "gone" from power in Iraq. Presidential spokesman Ari Fleischer cautioned that more fighting may lie ahead, but said there is no question that Saddam Hussein has lost control of the country.
U-S officials say they do not know the whereabouts of Saddam, his two sons, or other top Iraqi officials. In order to help coalition troops find key members of the regime, soldiers have been given decks of cards containing the names and faces of 55 key Saddam loyalists.