The Israeli military said Mondaythat a Hezbollah member was killed by the Israeli army during a clash in south Lebanon after a UN-brokered ceasefire took effect on the ground earlier in the day.

Media reports quoted an Israeli military source as saying that the Hezbollah fighter was killed after he opened fire on Israeli soldiers near the Litani River.

This is the first casualty after the UN-brokered ceasefire took effect earlier on Monday morning, said the source, without elaborating the clash.

But other army sources said that it did not know if the Hezbollah militant had been killed or wounded, though he was hit as the Israelis "fired in self-defense" at a group of armed Hezbollah fighters approaching in a threatening way.

On Friday, UN Security Council unanimously adopted a resolution calling for Israel's withdrawal and authorizing an increase of the existing UN force in Lebanon to 15,000 troops to help Lebanese government troops take control of south Lebanon as Israel withdraws.

The UN-brokered Israel-Lebanon cease-fire took into force at 0500 GMT on Monday morning following both Israeli and Lebanese approval on Sunday.