THE United Nations and United States warned Wednesday that civilians must be protected as forces battling Somalia’s Islamist fighters tightened the noose around the key insurgent bastion of Kismayo.More than 6,000 civilians have fled ahead of the anticipated assault on the strategic port city, the United Nations refugee agency UNHCR said Wednesday, with aid agencies preparing for a potential swift escalation of those needing support."We understand that humanitarian agencies have begun contingency planning to respond to the needs of those civilians fleeing from Kismayo,” the US embassy in Nairobi said in a statement."We call on all parties to ensure full, safe and unhindered access for humanitarian assistance to reach those civilians affected by the fighting.”Kenyan troops with the 17,000-strong African Union force, fighting alongside Somali militia forces opposed to the Al-Qaeda-linked Shebab, have moved to within some 40 kilometers (25 miles) of the southern Somali port city."The forces are pacifying the area....the march to Kismayo is still on and nothing will distract us from our mission,” said Kenyan army spokesman Cyrus Oguna, adding that the frontline was so far reported quiet on Wednesday.Mark Bowden, the United Nations Humanitarian Coordinator for Somalia met Wednesday with Kenyan officials following a "spike in civilian displacement” as people fled from the town, whose population is estimated at between 160,000 and 190,000.While Bowden said Kenya had vowed to provide humanitarian access to those in need, he repeated a call "for all parties to the conflict to make every effort to minimize the impact of conflict on civilians”.Residents and the multiple forces moving against the Shebab say the extremist fighters are leaving the port, with some moving forward to bolster frontline positions."There are reports that fighters from the Shebab are abandoning their stronghold at the port of Kismayo,” Ethiopia’s foreign ministry said in a statement.Ethiopia also has some 10,000 troops in southern Somalia, which it invaded last November to attack Shebab positions.But Shebab spokesman Ali Mohamud Rage has said his forces are battling far from Kismayo -- the only major town still held by the militants following a string of losses -- and that reports of a retreat were false.AFP