Helicopter-borne Israeli commandos raided Hezbollah positions today in what Lebanon called a "naked violation" of the UN-backed truce that halted Israel's 34-day war with the Shi'ite Muslim group.
Israel said the operation in the eastern Bekaa Valley aimed to disrupt weapons supplies to Hezbollah from Syria and Iran. Both countries deny arming the group.
Lebanese security sources said three Hezbollah guerrillas were killed in a dawn firefight with the Israeli commandos. The Israeli army said it had suffered one dead and two wounded.
"It is a naked violation of the cessation of hostilities declared by the Security Council," Prime Minister Fouad Siniora told reporters.
"Special forces carried out an operation to disrupt terror actions against Israel with an emphasis on the transfer of munitions from Syria and Iran to Hezbollah," Israel's army said.
The raid coincided with a Lebanese army drive to tighten its grip on the border with Syria. Thousands of troops deployed to block smuggling routes today. But the Israeli Foreign Ministry insisted Hezbollah arms shipments were continuing.
"The ceasefire in Lebanon is based on UN Security Council resolution 1701 which calls for a total international arms embargo on Hezbollah," said ministry spokesman Mark Regev.
"Israel reserves the right to act in order to enforce the spirit of the resolution."
Parliament Speaker Nabih Berri, Hezbollah's main ally in government, said and Mr Siniora had complained to visiting UN envoys and said he was sure the Hezbollah were too smart to retaliate.
The resolution adopted on August 11th ordered a "cessation of hostilities", halting a conflict in which at least 1,183 people in Lebanon and 157 Israelis were killed.
It ordered Israel to end "all offensive military actions" and Hezbollah to end all attacks.
It also called for an embargo on unauthorised arms supplies and for the Lebanese army to move to the south alongside a strengthened UNIFIL, the UN peacekeeping force in the area.
In his weekly radio address on today, US President George W Bush said the UN force would help the Beirut government restore sovereignty and "stop Hizbollah from acting as a state within a state."
The United Nations wants to field an advance force of 3,500 troops by September 2nd and the entire complement of 13,000 extra troops by November 4th.