Israel allowed the first truckloads of a rare shipment of construction materials into Gaza on Wednesday to permit the reconstruction of 10 privately owned factories, the Israeli military and Palestinian officials said. Until now, only international projects were allowed to import such materials, which Israel restricts because of concerns they could be used by militants who launch rockets at Israeli towns. Gaza, which is ruled by the militant group Hamas, is subject to an Israeli blockade that has been eased but includes restrictions on the movement of goods and people. The factories being rebuilt were destroyed or damaged in fighting in 2009.