JERUSALEM —  At least two people were dead and 12 injured Thursday following an explosion at a Tel Aviv (search) money changer's shop, Israeli police reported, rocking a nation already on edge over daily warnings about planned attacks by Palestinian militants.

The cause of the blast may be criminal, and not a terrorist attack, Israeli police said. Reports circulated that Israel's top mafia crime boss, Ze'ev Rosenstein (search), was seen rushing away from the scene after the explosion occurred around 12:30 p.m. in a crowded business district during lunchtime.

"We're treating it less as a terrorist attack and more as a criminal attack," said Israeli police spokesman Gil Kleiman. "It means that instead of looking for Palestinians, we'll be looking for Israelis."

The blast went off as Rosenstein entered the money changer's shop, witnesses said. Rosenstein's lawyer confirmed his client was present at the scene and was wounded.

Rosenstein was recently released from police interrogation. He had been taken into custody after a hit man reportedly claimed Rosenstein had ordered hits on some of his rivals. Police later said Rosenstein's accuser was lying and released Rosenstein.

After the blast, cars on both sides of the road were damaged.

"I was next to it, the whole window blew out," an unnamed eye witness told Israel Radio.

Among crowds gathered at the site of the blast, some people said they were relieved to learn the bomb appeared to have been a criminal hit, not a terrorist attack. Some stood around laughing and chatting.

An elderly woman called out from an apartment window to a friend below, "It's just criminal."

The explosion, if a bombing, would be the first major attack on Israeli civilians since the bombing of a restaurant in the northern Israeli city of Haifa (search) in October, which killed 21 people.

The Associated Press contributed to this report.