They said the American soldiers confronted no resistance in the northern town which was deserted of Iraqi regular troops and much of its population of

US helicopters dropped soldiers in a central square near the headquarters of Saddam's Fedayeen militia, again encountering no resistance, witnesses in central Tikrit said.

Several tanks took up positions around Saddam's palace in the town and on the main street.

Earlier, witnesses said "around 20 tanks" entered the city centre along the main road from Kirkuk, further north, across a heavily bomb-damaged bridge over the River Tigris, the witnesses said.

Control of the Kirkuk road gives US troops access to their forces deployed in the Kurdish regions of northern Iraq.

The US forces bombarded northern Tikrit ahead of the final push, an AFP reporter in the town said.

Throughout the night, US jets carried out intermittent air strikes to the south and west of Saddam's traditional power base, where loyalist defence lines were said to have been concentrated.

An official announcement of the fall of Tikrit would signal the symbolic end of Saddam's regime in the US-led war launched on March 20.

Tikrit lies about 180 kilometres (115 miles) north of Baghdad and was considered the last major town not under control of the coalition forces.

Some 250 US armoured vehicles entered the city and Brigadier General John Kelly said five Iraqi tanks had been destroyed on the outskirts and at least 15 people killed in firefights, Canadian journalist Matthew Fisher, "embedded" with the marines, told CNN.

The US assault apparently ignored an appeal Sunday from 22 Tikrit tribal leaders for an end to coalition strikes on Tikrit so a peaceful surrender of the pro-Saddam militia there could be negotiated.

"We are ready to surrender, but let them stop their bombardments. After that we are asking for just two days to persuade the fedayeen to lay down their arms," Yussuf Abdul Aziz al Nassari, representing the tribal leaders, told AFP.

Earlier Sunday, no militia or Iraqi troops were seen in the town centre, only a number of armed residents who said they wanted to prevent looting that has occurred in every Iraqi city abandoned to the coalition by forces loyal to Saddam.

The residents, carrying Kalashnikov assault rifles and grenades, said they would surrender to US forces if these were not accompanied by Iraqi opponents of Saddam's regime, notably Shiites and Kurds.

SPACE.WIRE