Lebanese soldiers outside the Nahr al-Bared camp outside Tripoli, 24 May 2007

Lebanese troops and Islamic militants inside a Palestinian refugee camp exchanged heavy fire late Thursday, breaking a two-day-old truce.

The gunfire and shelling lasted less than an hour at the Nahr al-Bared camp outside the city of Tripoli, before dying down. A shaky ceasefire had largely held since Tuesday.

Earlier Thursday, Lebanese Prime Minister Fuad Siniora vowed to crush the Islamic militants in the camp. Mr. Siniora said in a nationally televised speech that the army had been a victim of a "terrorist organization."

The Fatah-al-Islam militants holed up in the refugee camp said they will abide by the truce, but will not surrender and will fight if attacked.

About 75 people - soldiers, militants and civilians - have been killed since the fighting began Sunday.

On Wednesday, Lebanon's Defense Minister Elias Murr issued an ultimatum to the militants, saying they must surrender or face further military action.

Relief workers say as many as half of some 30,000 residents of the camp have fled since the truce went into effect. Most headed to Tripoli and another nearby Palestinian refugee camp, Beddawi.

The new French foreign minister, Bernard Kouchner, arrived in Beirut for talks with Mr. Siniora and other senior officials, including the speaker of Parliament, Nabih Berri.

France's Foreign Ministry issued a statement saying Kouchner's trip aims to reaffirm French solidarity with Lebanon during what it called this "critical period." Lebanon is a former French colony.

The battles on the outskirts of Tripoli are said to be the worst internal fighting since Lebanon's 15-year civil war ended in 1990.

Some information for this report was provided by AFP, AP and Reuters.