The failed attempt to explode a large car bomb in a shopping centre in Haifa on Saturday night has intensified fears of a possible wave of terror attacks.

The Israeli police and security forces have forbidden publication of any technical details of the car bomb. However, its size, described by explosives experts as “equal to 15 suicide bombers”, and the sophistication of the methods used to smuggle it into Haifa and the shopping centre car park, is of an order not seen in Israel for more than five years.

Intelligence sources fear that the bomb was a joint operation by Hamas and Hizbollah operatives, possibly with Iranian assistance.

Israel’s operations in the West Bank against the terror infrastructure of Palestinian organisations in 2002-2005 brought a dramatic reduction in bombing attacks within Israel.

The fact that Palestinians have resorted to “low-tech” bulldozer attacks against civilians in Jerusalem underscores their inability to launch the kind of attacks carried out in previous years.

The security services have yet to reveal who shot two traffic policemen as they patrolled the Jordan Valley earlier this month.