According to the news, who claimed responsibility for the rocket attack?

Palestinian rockets fired from the Gaza Strip crashed into the battered Israeli border town of Sterot. The Islamic militant group Hamas claimed responsibility for the attack, in which a 36-year-old Israeli man was killed when his car took a direct hit. He was the second Israeli fatality in the past two weeks, during which time Palestinian militants have fired more than 230 rockets at Israel. The attack brought a stern warning from Prime Minister Ehud Olmert at the weekly Cabinet meeting in Jerusalem. "There is no immunity for anyone involved in terror," Mr. Ohnert said, hinting that the leaders of Hamas could be targeted. "We will decide when, how and to what extent we will act," he said. Mr. Olmert spoke hours after Israel launched a fresh wave of air strikes on Hamas targets in Gaza. About 50 Palestinians, most of them militants, have been killed in the raids which began 12 days ago. Hamas says it is absurd to talk about a truce while Israeli air strikes continue. And in the wake of the deadly rocket attack, Israel’s offensive shows no sign of letting up.