MOGADISHU, Somalia (AP) _ Hundreds of Islamic militiamen in heavily armed trucks headed Saturday to the strategic town of Kismayo in what appeared to be an imminent takeover attempt of one of the last seaports outside their control in Somalia, witnesses said.

Key leaders of the Islamic militia _ which controls the capital, Mogadishu, along with much of southern Somalia _ have been in Kismayo for several days in direct challenge to the warlords who are in control there.

Fearful residents of the town, some 260 miles southwest of Mogadishu, have been fleeing across the border to Kenya in case fighting breaks out.

``I saw 50 trucks from the Islamic courts and more than 300 militiamen who were heading to Kismayo,'' Quasim Munye told The Associated Press from the coastal town of Brava, which is on the only road that leads to Kismayo. ``The trucks were huge and the militias well-prepared.''

Somalia has not had an effective national government since 1991, when warlords overthrew dictator Mohamed Siad Barre and then turned on one another, throwing the country into anarchy.

An official government was formed in 2004 with U.N. help in hopes of restoring order after years of lawlessness. But the Islamic movement seized Mogadishu in June and now controls much of the country's south.

The government controls just one town, Baidoa, 150 miles from the capital, but it has a strong ally in Kismayo. The government's defense minister, Col. Barre ``Hirale'' Aden Shire, is a member of the Juba Valley Alliance that rules the town.

The United States has accused the Islamic group of sheltering suspects in the 1998 bombings of U.S. embassies in Kenya and Tanzania. Al-Qaida chief Osama bin Laden has portrayed Somalia as a battleground in his war on the U.S.

The group's strict and often severe interpretation of Islam raises memories of Afghanistan's Taliban, which was ousted by a U.S.-led campaign for harboring bin Laden and al-Qaida fighters. Still, many residents credit the courts with bringing a semblance of order.

Also this week, Islamic leaders in the capital banned the sale of a leafy stimulant called qat, which is wildly popular among Somalis, during daytime in the Muslim holy month of Ramadan, which begins this weekend. Islamic officials in Balad, about 18 miles from the capital, banned qat altogether during Ramadan.

Islamists consider qat un-Islamic but have generally tolerated it since they came to power. Users chew qat like loose tobacco and experience a mild buzz that lasts for anywhere between 90 minutes to a few hours. It can also cause an elevated heart rate and create a feeling of euphoria.