Twenty-three soldiers and 19 militants died in the clashes, which erupted before dawn on the edge of the Nahr al-Bared camp and in the nearby Sunni Muslim city of Tripoli in north Lebanon.

[View Video of the outbreak of violence]

A cabinet minister said the fighting with Fatah al-Islam, which the government says is backed by Syria, seemed timed to try to derail U.N. moves to set up an international court to try those suspected of carrying out political killings in Lebanon.

Four of the soldiers were killed in an attack on an army patrol in al-Qalamoun just south of Tripoli, Lebanon's second largest city, security sources said.

They said 15 militants were killed when troops stormed buildings they had occupied in Tripoli and four in the camp, home to 40,000 refugees. Medical sources in the camp said six civilians, including two children, were killed and 60 wounded.

The army was blasting militant positions in the camp with tank, mortar and machinegun fire, a military source said. More than 20 soldiers were wounded overall, the source added.

Fatah al-Islam, a Sunni group, said the army had launched an unprovoked attack.

"We warn the Lebanese army of the consequences of continuing the provocative acts against our mujahideen who will open the gates of fire ... against (the army) and against the whole of Lebanon," it said in a statement faxed to Reuters.

The authenticity of the statement could not be verified.

The army had tightened its grip around Nahr al-Bared after four Fatah al-Islam members, all Syrian nationals, were charged with planting bombs on two buses in a Christian area near Beirut in February. Three civilians were killed in those attacks.

Fatah al-Islam is known to have Lebanese, Syrian and Palestinians in its ranks. Its leader is a Palestinian.

U.N. TRIBUNAL

Cabinet minister Ahmad Fatfat, speaking in Tripoli, said the violence was part of efforts to sabotage U.N. moves to set up the international tribunal to try suspects in the 2005 assassination of former Prime Minister Rafik al-Hariri.

A U.N. inquiry has implicated Syria and Lebanese officials in the Hariri killing. Damascus denies any involvement.

Syria also denies any link to Fatah al-Islam, whose leader, Shaker al-Abssi, says the group has no organizational links to al Qaeda but agrees with its aim of fighting 'infidels'.

Syria said it had closed two border crossings to north Lebanon due the violence. The main crossing remained open.

Fatfat told Lebanon's pro-government Future TV: "There is someone trying to create security chaos to say to world public opinion: 'Look, if the tribunal is established, there will be security trouble in Lebanon'."

Lebanon's anti-Syrian March 14 movement, which dominates the government, described Sunday's clashes as a "criminal attack which comes as a translation of the threats made by the head of the Syrian regime to set Lebanon ablaze if the international tribunal is established."

The United States, France and Britain last week circulated a draft U.N. resolution that would unilaterally set up the court, which is at the heart of a political crisis in Lebanon.

Machinegun fire and explosions rocked the Nahr al-Bared area when the fighting broke out overnight. Residents were trapped indoors and pleaded for a ceasefire to evacuate the wounded.

The Lebanese army sent reinforcements to the outskirts of the camp, but did not push inside in line with a 1969 Arab agreement which bars it from entering Palestinian camps.

An army statement said the clashes began when Fatah al-Islam attacked army posts around the camp and in northern Tripoli.

Television pictures of a building stormed by the army in Tripoli showed corpses, some charred, on a floor strewn with rubble.

Security forces had also been trying to arrest Fatah al-Islam members suspected of robbing a bank on Saturday, security sources said. A group of them had been detained.

Fatah al-Islam was formed last year by fighters who broke off from the Syrian-backed Fatah Uprising group.
Top Picture: Residents greet Lebanese army troops after clashes with militants of Fatah al-Islam group in Tripoli, northern Lebanon, May 20, 2007.

Sources: Reuters , Ya Libnan