Israeli army said on Saturday evening that an Israeli helicopter was shot down in south Lebanon, with four crew members on board, the pan-Arab al-Jazeera satellite TV reported.

Military sources said one crew member was confirmed dead, adding that the fate of the other three crew members is not yet known.

The army estimated that it was shot down by an anti-missile fired by Hezbollah guerrillas, Israeli newspaper Yedioth Ahronoth reported.

Earlier, Lebanese Hezbollah claimed on its al-Manar TV that its guerrillas shot down an Israeli military helicopter in southern Lebanon, at least four helicopters were flying in the region at the time of the incident.

The Israeli helicopter was shot down in the Maryamein valley by one of its new missiles named the "Waad", said the group.

Since Friday night, an airlift of IDF troops has been conducted from the northern Israeli border to Lebanon, and the helicopters landed a great number of forces inside the field, according to Yedioth Ahronoth.

This is the fourth aerial accident since the onset of the Israeli military operation in Lebanon, said the report.

On July 21, two Apache combat helicopters on their way to Lebanon to assist IDF forces near Avivim collided and then crashed in the Ramot Naftali area, south of Kiryat Shmona, killing an Israel Air Forces (IAF) official and wounding three soldiers.

In addition, two Israel Air Forces soldiers were killed on July 24 after their Apache helicopter suddenly hit a power line and crashed on the ground in northern Israel, the report added.