At least nine Israeli soldiers were killed in a fierce fighting with Hezbollah guerrillas in southern Lebanon today, pan-Arabic TV channel al-Jazeera reported.

The Wednesday fighting broke out when Israeli forces advanced toward southern Lebanese town of Bint Jbeil and attempted to take one of Hezbollah strongholds there, said the report.

However, some other media reports said that 12 Israeli soldiers were killed in the fighting with Hezbollah on Wednesday. No confirmation is available at the moment.

Israeli army intensified air and ground offensives in southern Lebanon in past days in an effort to eradicate Lebanese Shiite group Hezbollah and create a buffer zone in southern Lebanon.

On Tuesday, a missile fired by Israeli warplane hit a UN post in southern Lebanon, killing four UN peacekeepers.

Israeli Prime Minister Ehud Olmert expressed his deep regret in a phone call to UN Secretary General Kofi Annan on Wednesday, saying that it was a mistaken bombardment but not a deliberate action.

Also on Wednesday, an international conference on Lebanon was being held in Italian capital of Rome.