Hundreds have been killed in clashes between Somalia's Islamic militia and the country's secular government, officials said Friday as the U.N. took advantage of a brief lull in fighting to push for peace.

Although sporadic gunfire and shelling could still be heard around the headquarters of the Ethiopian-backed government, residents and officials said the worst of the current fighting was over. New attacks were feared.

Thousands of Somalis have fled their homes as troops loyal to the two-year-old interim administration fought Islamic fighters who had advanced on the regime's only stronghold, Baidoa.

Islamic forces who have declared they want to bring the whole country under Quranic rule vowed to continue attacks to drive troops from neighboring Ethiopia, a largely Christian nation that is providing military support, out of Somalia.

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In Kismayo, a strategic seaport captured from the government by Islamic militia in September, several foreign Arab fighters were seen by residents getting off ships.

The U.N. issued a statement in the Kenyan capital, Nairobi, Friday calling for an "immediate end" to the conflict. It accused both sides of using increasing numbers of child soldiers.

"This conflict will push the children of Somalia into further dire crisis," the U.N. said.

It was unclear how long the guns would remain quiet as earlier Friday four Ethiopian attack helicopters and around 20 tanks headed for battle, witnesses and a government official said.

Sheik Ibrahim Shukri Abuu-Zeynab, a spokesman for the Islamic movement, told reporters in the capital, Mogadishu, the fighting would worsen.

"We will now start our real attack against the invaders and would not stop until we force the Ethiopians out of our country," he said.

Fighting has occurred in at least three areas near Baidoa: Idale, 37 miles southwest, which the Islamic group claim to have captured: Dinsor, 75 miles south; and Daynunay, a military base 15 miles northeast of Baidoa on the road that leads to Mogadishu.

Gunfire could still be heard near Idale where Islamic militia told The Associated Press that Ethiopian troops were trying to recapture the town.

Much of the fighting took place around government defensive positions in what analysts say was heavy probing skirmishes from both sides.

Bodies lay in the streets of villages where attacks had taken place Thursday night, and families began to abandon their homes, crops and livestock, fearing worsening fighting. Hundreds of people in areas held by the Islamic forces also were fleeing south to Mogadishu.

"I think we have lost hundreds of our animals in the fighting, most of them were caught in the crossfire," said Malable Aden, who reached Mogadishu by car. "We were supposed to reap our harvest of this season, but unfortunately we were forced to leave them behind for the pigs and birds to destroy them."

The leader of the Council of Islamic Courts, the umbrella organ for the Islamic militia, said Thursday that Somalia was in "a state of war" and called on all Somalis to fight Ethiopian forces in the country. Ethiopia denies its forces are fighting, but says it has deployed several hundred military trainers in support of Somalia's U.N.-backed transitional government.

Islamic movement leaders "are claiming that Ethiopia is fighting against them and this is totally false," said government spokesman Zemedkun Teckle. "If the time comes that we have to fight, it will be very clear to everyone and there will be no doubt because we will announce this to our people."

Somalia has not had an effective government since 1991. The country's secular interim government, set up in 2004 and backed by the U.N., has rejected religious rule. Muslim leaders have insisted on an Islamic government.

Somalia's internationally recognized interim government holds only a small area around the central town of Baidoa, about 140 miles northwest of the capital, Mogadishu. The Islamic militiamen, meanwhile, control Mogadishu along with most of southern Somalia.