U.S. forces have taken control of more of Baghdad, after routing pockets of resistance in the city. But the advance of troops has brought looting to the new areas.

American forces secured two more bridges over the Tigris River on Saturday, but as the troops advanced, looters followed closely behind, ransacking government buildings.

There were similar scenes in cities across the country in the past several days.

Humanitarian aid groups are urging U.S. and British forces to do more to restore public order, saying international law requires occupying powers to ensure the safety of civilians in areas under their control.

U.S. Central Command spokesman, Brigadier General Vince Brooks, says coalition forces are fulfilling their responsibilities in that regard.

"In areas where we're present, as I stated, we find reports from commanders that there is an impact that contributes to security just by the presence that's there," General Brooks said. "But we can't be present in all locations, and so, there are clearly some places where there is unrest."

The city of Mosul in northern Iraq, like Baghdad, was the scene of widespread looting. But General Brooks says local citizens have established a neighborhood watch program there, and are helping restore order.

Two drones, or remotely piloted aircraft, were reported to have been found at a phosphate plant in western Iraq. But officials said further investigation would be required to determine if the aircraft could be used to deliver chemical weapons. And, 15 undamaged fixed-wing fighter aircraft were found at an airfield in the area.

General Brooks also announced the detention of 59 men of military age, who were stopped at a checkpoint as they were trying to make their way to Iraq's western border.

"Among their possessions were letters offering financial rewards for killing American soldiers and $630,000 in $100 bills," he said.

Coalition commanders say Iraqi forces may try to make a last stand in Saddam Hussein's hometown of Tikrit the one major Iraqi city not yet in coalition hands. Iraqi troops are reported moving toward the city, which is 150 kilometers north of Baghdad. U.S. aircraft have pounded Republican Guard positions around Tikrit for days, and American ground forces are less than 100 kilometers away.

Elsewhere, U.S. Marines have found three journalists in a Baghdad hospital and the body of a fourth apparently killed during a firefight in the Iraqi capital.

Two of the journalists were injured Tuesday, when they were caught in a firefight at the Palestine Hotel, where most of the international reporters have been staying. One other journalist found at the hospital was unharmed. Their names have not been released.