Hamas: Sharon has opened the gates of hell

Hamas leaders on Monday vowed to "cut off" the head of Prime Minister Ariel Sharon, after their spiritual leader Sheikh Ahmed Yassin was killed in a missile strike by Israeli gunships in Gaza City, reports Haaretz newspaper.

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The paper quoted leaders of the radical Islamic group as saying: "Sharon has opened the gates of hell and nothing will stop us from cutting off his head."

Hamas official Ismail Haniyeh, a close associate of Yassin in Gaza, was quoted as saying: "Words cannot describe the emotion of anger and hate inside our hearts."

Another Hamas leader said Islamic groups around the world will join forces for a retaliatory strike and indicated that the United States could be a target.

"The Zionists didn't carry out their operation without getting the consent of the terrorist American administration, and it must take responsibility for this crime," Hamas said in a statement.

Describing the scene in Gaza City, Haaretz correspondent Arnon Regular wrote: "Tens of thousands of Palestinians, many in tears, poured into the streets of Gaza City immediately after the strike. Gunmen fired into the air and militants threw dozens of pipe-bombs to express their outrage."

The Palestinian Authority has declared three days of mourning.