(CNN) -- As dozens of Palestinian rockets rained down on southern Israel, the country's air force carried out new raids on positions in Gaza on Wednesday. Two days of airstrikes have killed four Palestinians, at least two of them identified as militants. Attacks and counterattacks between the two sides are a frequent occurrence but appear to have escalated in the past two days. On Tuesday night, the Israeli military said its aircraft had targeted two rocket-launching squads in northern Gaza as they prepared to fire into southern Israel. That attack killed two militants from Al-Qassam, the military wing of Hamas, and wounded two others.
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NEW: "Hamas will receive its punishment," Ehud Barak says
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Attacks and counterattacks have escalated in the past two days
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The Palestinian rocket attacks wound three Thai workers in Israel
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The emir of Qatar visits Gaza and will increase aid
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But the barrage of rockets continued, with more than 65 fired from @placeholder in an eight-hour period, the military said Wednesday morning.
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Whoever intends to attack @placeholder citizens needs to know that he will bear the consequences."
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"There is no way to eliminate the hatred or hostility entrenched in @placeholder.
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But she expressed continuing concern over the "destabilizing role" of Hamas, which has governed @placeholder since 2007.