Israeli tank shells crashed into a residential neighborhood, killing at least 18 people, including eight children, in their sleep early Wednesday, Palestinian witnesses and officials said. Palestinian Prime Minister Ismail Haniyeh said efforts to form a national unity government were suspended because of the attack. Israeli Defense Minister Amir Peretz ordered the army to halt artillery attacks in Gaza. But a government spokesman said Israel will continue its operations in Gaza aimed at halting Palestinian rocket attacks, the Associated Press reported.