Gaza/Tel Aviv - The death toll of five days of ferocious Israeli air raids against Hamas targets in Gaza has reached 400, de- facto health minister Basam Naim said Wednesday.

Some 2,000 Gazans have been injured, about 300 of whom are in serious condition, causing the death toll to rise rapidly, he said.

The official of the radical Islamic movement ruling Gaza claimed that half of Gaza's ambulances were out of service due to lack of petrol.

Four Israelis have also been killed and several dozen injured by Palestinian rocket attacks at southern Israel since its Operation "Cast Lead" got underway Saturday.

At least five imported, Russian-type Grad rocket have hit the southern Israeli city of Beersheba since late Tuesday, located some 40 kilometres from Gaza.

They marked the deepest rocket attacks inside Israel since Hamas and other militant factions active in Gaza first fired rockets at Israeli towns and villages near the strip seven years ago.

One of them struck a high school which was vacant after a last- minute decision late Tuesday to cancel classes in the city of 186,000.

Altogether, militants showered southern Israel with some 60 rockets Wednesday, including a number of Grads. (dpa)