MOGADISHU, Somalia (AFP) — Kenyan troops from the African Union force in Somalia entered the southern port of Kismayo for the first time yesterday, witnesses said, three days after launching a beach assault that led Islamist insurgents

to withdraw.

Somali militia who have been fighting alongside the Kenyans also moved in, raising fears that the second city in southern and central Somalia — which the Shebab had run for four years could descend into chaos.

The Kenyans "arrived from the west of the city and are taking up positions," said Aden Ismail, a local trader.

At least two other witnesses confirmed to AFP by phone that Kenyan soldiers from the 17,000-strong African Union Mission in Somalia (AMISOM) had entered the city, after remaining on the outskirts for more than two days.

It was not clear if the Kenyans remained in the city at nightfall.

Other witnesses said they had seen only Somali militia in town.

"The ones I saw were maybe around 120 armed militants in dark green khaki uniform... but the Kenyan troops are not with those I have seen so far," said Abdirahman Said, a Kismayo resident.

He said some of the fighters carried a flag reading "Ras Kamboni", the name of a militia group with whom the Kenyans have been working.

Dhuhulow Abdirahman, another resident, expressed concern about the presence of Ras Kamboni in the city.

"They are from one clan and other clans will protest if they take control of the port and the airport," he said.

Residents have reported the presence of clan militia opposed to Ras Kamboni on the streets of the port city ever since the Shebab pulled out early Saturday.

Kismayo was the main target of an operation launched by the Kenyan military almost a year ago. Its troops have since been integrated into AMISOM, whose bid to stamp out the insurgency is also supported by Ethiopia in western regions.

Observers have said that reclaiming Kismayo would cut off the Shebab's supply lines, strip them of vital funding and spell the end of their ability to control large swathes of land in southern Somalia.

The US praised AMISOM yesterday for driving out Al-Shebab, and urged Somali leaders to work to stabilise

the town.

"We applaud the work of AMISOM and what they have done in helping to degrade and defeat and push Al-Shebab out of Somalia's main cities," said the top US diplomat for Africa, Johnnie Carson.

"We believe that this will help to bring about a return to stability in Somalia, and reduce over time the terrorist threat to Somalia and neighbouring states."

Carson called Somalia "a good news story for the region", pointing to the nation's new constitution and newly elected parliament and president, after years of lawlessness.

Offering help to build a new Somali military, he called on the government in Mogadishu to "go in very quickly and establish a political stability, and a political system that takes into account the various clan and sub-clan interests" in Kismayo.

The power vacuum created by what the Islamists called their "tactical retreat" from Kismayo — after initially vowing the Indian Ocean would

turn red with AMISOM blood — had left the town exposed to chaos and looming shortages.

It was not immediately clear how many AMISOM troops were taking up position in Kismayo, but residents had mixed feelings about the change.

Asha Mohamed Aden, a seller of second-hand clothing, said she had seen "heavily armed Kenyans" entering the city along with Somali officers.

"They are carrying a lot of weapons," she said.

"Some people are happy to welcome them because they were fed up with the misrule" of the Shebab Islamists, another resident, Abdullahi Farey Hassan, told AFP by telephone, adding that he himself had "reservations".

Since the retreat of the Shebab, who ruled Kismayo with an iron fist, unidentified gunmen have killed at least three civilians, including a traditional leader, according to residents interviewed by phone.

The group's pullouts from its other key bastions elsewhere in Somalia have heralded a return to guerrilla tactics, including suicide bomb attacks.

Somalia's new President Hassan Sheikh Mohamud praised AMISOM Monday for forcing the Shebab to vacate the city.

Somali government sources said

the administration is working on

plans to mediate between the clans

who are arguing over control of

the town in order to facilitate an

"all-inclusive administration" and avoid

further violence.

The Shebab used Kismayo as an export hub for the illegal charcoal trade and the port had been their de facto capital since they abandoned

fixed positions in Mogadishu last year, also under increased military pressure from AMISOM.

The port city has been largely off-limits for most foreign and local journalists and aid groups.

The Shebab still control the town of Jowhar, some 300 miles northeast of Kismayo, and one small port town, Barawe, lying some 140 miles up the coast from Kismayo.

Kismayo had also been a symbol of the extreme form of sharia — or Islamic law — the Shebab want to impose across the country since 2008, when they stoned a teenage girl in public on charges of adultery.