A 200-pound car bomb malfunctioned near a crowded mall in the Israeli port city of Haifa on Saturday night, averting what could have been one of the largest such attacks in Israel in the past several years, police said.

A bomb squad was called to the Lev Hamifratz shopping center after a small explosion, possibly a detonation charge, inside a Subaru in the mall's parking lot, according to police.

Police found what an official said were roughly 200 pounds of explosives that had failed to detonate. The amount was enough to have caused a devastating blast at a time when the popular mall was crowded following the end of the Jewish Sabbath. The device was packed with ball bearings, according to police. There were no reported arrests as of late Sunday night.

Police spokesman Mickey Rosenfeld said that the car had been stolen from East Jerusalem and that officials are trying to determine the source of the explosives and the route traveled by those responsible. The fact that the explosives-laden vehicle was able to enter a major civilian area deep inside Israel without detection constituted a major breach of Israel's normally tight security system.

Violence in cities like Haifa, well outside the disputed territory of the West Bank and beyond the range of the rockets fired from the Gaza Strip, has declined in recent years. There was only one suicide bombing inside Israel in 2008, which killed one Israeli. The last vehicle bomb detonated deep inside Israeli territory was in 2002, when a truck carrying about 175 pounds of explosives rammed a bus on a road outside Tel Aviv and killed more than a dozen people.

Israelis cite a number of reasons for the decline in such attacks, including construction of a security barrier around much of the West Bank. Palestinians say the barrier is intended to limit their movement and to take their land.

Israeli Prime Minister Ehud Olmert warned Sunday that "we should not delude ourselves" into thinking that the barrier or other methods are foolproof.

"This was, purely, a terrorist attack," he said.

Israeli news media reported that a little-known group associated with the Galilee region of northern Israel had asserted responsibility, but officials said their investigation is continuing.