Hamas' militant wing claimed responsibility for a homemade rocket attack on a vacant high school in southern Israel on Tuesday, and Prime Minister Ehud Olmert called it "a major escalation [of] the war of terror" against Israel.

The missile, fired from the Gaza Strip, caused extensive damage to the school but no injuries in the city of Ashkelon, the army said, and the militant wing of Hamas later sent a fax to The Associated Press office in Gaza City saying it had carried out the attack.

In a speech at the home of U.S. Ambassador to Israel Richard Jones, marking the American Fourth of July holiday, Olmert said: "This is a major escalation in the war of terror that the Hamas organization is responsible for."

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