An Israeli army spokeswoman said the two US-built Apache helicopters crashed on Thursday night on a road near Ramat Naftali, 10km from the border with Lebanon.

Initial checks indicated that the crash was an accident and was not caused by enemy fire, the spokeswoman said.

Each helicopter carries a two-person crew.

On Thursday an Israeli F-16 fighter jet crashed shortly after take-off in another accident in southern Israel. Both crewmen survived.

Elsewhere on Friday, Israel said four of its soldiers had been killed in heavy fighting with Hezbollah fighters just inside the Lebanon border on Thursday.

Several other soldiers had been injured, a military spokesman said.

The Israeli army said the soldiers had been searching for Hezbollah bases and weapons.

Fewer rockets

Hezbollah said it lost two of its fighters in the clashes.

The fighting occured in the Lebanese village of Maroun al-Ras, Arab media reported.

Israeli police also said the number of Katyusha rockets fired by Hezbollah at northern Israel from Lebanon on Thursday was fewer than the daily average over the last eight days.

However, police urged the 1.2 million Israelis living in the north of the country to remain vigilant and to stay in shelters.