An AFP correspondent said the streets were calm and that five armored vehicles were in the city center, which appeared to have been deserted by Iraqi regular forces and much of the population.

The vehicles and 900 Marines were deployed in a main square of Tikrit, 180 kilometres (115 miles) north of Baghdad, after US troops entered the city before dawn, a sergeant said.

"We didn't encounter any resistance in the city, but only on the outskirts last night. We had bad ambushes there," Sergeant Robert Chute said in Tikrit, Saddam's hometown and a traditional stronghold of his Baath party.

Firefights with what Chute believed to be Iraqi soldiers had left at least one Iraqi dead, while US units reported no casualties.

At the US Central Command's war headquarters in Qatar, British Group Captain Al Lockwood was upbeat, saying "there is a very good chance that once Tikrit has fallen the war will have finished.

"Clearly we are at a point when the decisive military operations that were focused on removing the regime ... that work is coming to a close," Brigadier General Vincent Brooks said at Centcom's forward base at As-Saliyah, Qatar.

"We believe our decisive operations campaign will be measured in weeks not months," he said at the command's war headquarters.

Outside the center of Tikrit, witnesses reported gunfire as residents warded off looters, but there was no immediate confirmation of the report.

US troops aboard four helicopters landed near the Tikrit headquarters of Saddam's Fedayeen militia but encountered no resistance, witnesses said.

Tribal chiefs had sought to negotiate a peaceful entry by coalition troops, but intermittent air strikes could be heard on the city's outskirts throughout the night.

Marines seized the presidential palace in Tikrit, where they met no resistance, acording to Centcom

Fighting in the city fell well short of the feared last stand by Saddam's closest tribal allies.

"There was less resistance than anticipated," Brooks said.`

He stressed that "potential for combat action is not yet over" in Iraq, but said it would be "much more localized when it occurs; it won't be on a widespread scale."

He said operations were focused "on eliminating any potential remaining regime leadership or forces within Baghdad and the areas north of Baghdad."

There were still sporadic bursts of fighting in Baghdad, where marines exchanged fire with unidentified targets around the Palestine Hotel in the city center overnight, AFP journalists reported.

The marines occasionally opened fire with automatic weapons and fired flares around the hotel, which houses most foreign media in the Iraqi capital.

Brooks said US troops found aircraft, weapons, ammunition and vehicles used by the regime, and in one case discovered 12 surface-to-air missiles.

In the northern Baghdad suburb of Saddam City, a firefight between Arab volunteers and Iraqi combatants left two dead Monday morning, Iraqi participants said.

Meanwhile, US troops were trying to maintain some order in Baghdad, wracked by days of looting since Saddam's 24-year grip on the Iraqi capital collapsed last week.

Iraqi police cars, escorted by US forces, started joint patrols of Baghdad's streets for the first time since the city came under American control.

US officials have begun trying to rebuild the Iraqi police force as well as drawing people back to key sectors such as the electricity department.

In the main northern cities of Mosul and Kirkuk, calm had returned Sunday after two days of looting and intercommunal fighting, with US troops reassuring Turkey by replacing Kurdish fighters in the oil-rich cities.

Mosul police were back on the streets while vigilantes were also trying to restore order in the city of 1.5 million, where as many as 20 people were killed and 200 wounded in two days of fighting between Arabs and Kurds.

Kurdish residents and members of the Free Iraqi Forces -- part of the US-backed Iraqi National Congress (INC) umbrella opposition group -- were sharing the task of protecting the city's infrastructure, US military sources said.

The situation was similar in Kirkuk, the other northern oil hub, where calm was slowly returning to the streets.

US forces moved to oil fields in the north and coalition forces now control all Iraq's oilfields, according to Centcom.

In the south, British troops were beginning joint police patrols with Iraqis in the city of Al-Fao, a reporter said. In Basra 200 volunteers joined with coalition troops to patrol the city, according to Brooks.

In central Iraq, a group of about 50 gunmen surrounding the Najaf home of top religious authority have withdrawn following the intervention of several tribal chiefs, a Kuwaiti Shiite cleric said.

He said the intervention by tribal leaders helped end the presence of the armed men who demanded that Ayatollah Ali Sistani leave the town.

burs-pfm/al

SPACE.WIRE