NAIROBI, Dec. 31 (Xinhua)--Somali Islamist militiamen are on Sunday fighting Ethiopian and Somali government troops advancing towards their last major stronghold in the port of Kismayo.

    Reports reaching here from the strategic town said artillery fire has been reported near the town of Jilib , close to Kismayo.

    "Fighting has started," a resident of the town of Bulobaley reportedly said. "Several mortars and rockets have hit the town."

    "Most of the mortars and rockets that have hit the town have fallen on deserted houses. I don't know if there are any wounded," the resident, who sought anonymity, said.

    The Islamists set up a new base in Kismayo shortly after being driven out of the capital, Mogadishu , last Thursday by Somali and Ethiopian troops.

    Sources said Islamist fighters have taken up positions in Jilib, just north of Kismayo, and residents there are fleeing.

    Reports from the region say Ethiopian warplanes have been flying over Kismayo, and the Islamists may have mined the road to it.

    The Islamist militia have vowed to resist the Ethiopian and Somali government troops who forced them out of the capital on Thursday.

    Islamist leader Sheikh Sharif Ahmed has said his forces are "ready to fight the enemy of Allah" and had only left the capital of Mogadishu "to prevent bloodshed."

    Jilib is a gateway to the south of the country and the Islamist militia are likely to use the town to block any further advance.

    Some 3,000 Islamist fighters are believed to be in Kismayo, some300 km south-east of Mogadishu , towards the Kenyan border.

    Ethiopian artillery and troops officially entered Somalia , joining fighters loyal to Somalia 's interim government, to repel an Islamist assault on the government stronghold of Baidoa.

    Thousands of civilians in the area around Jilib have been fleeing their homes in anticipation of heavy fighting.

    Kenya has re-enforced security along its border in an effort to prevent Islamist militiamen from crossing over.

    Somalia 's transitional government has called for talks with the Islamists. But the Islamists say they will not enter any dialogue unless Ethiopian forces vacate the country.

    Somalia has not had an effective central government since 1991,when warlords overthrew dictator Mohamed Siad Barre.