GAZA - Israel has cut back lumber shipments to the Gaza Strip, Palestinian importers said on Monday, adding to restrictions that could hamper housing reconstruction after last summer's war.Israeli authorities overseeing the transfer of goods to the Hamas Islamist-run enclave were not immediately available to comment.Israel tightly controls the transfer of construction material to Gaza, saying Hamas could use it to rebuild military infrastructure. Palestinian political in-fighting has also delayed widescale reconstruction of tens of thousands of homes damaged or destroyed in 50 days of fighting.According to Gaza importers, 200 cubic meters (260 cubic yards) of lumber used in the construction industry had been brought into the territory daily, and those shipments would now be banned.The number of planks used by furniture factories would be reduced from 6,000 a day to 2,400, the importers added, citing directives they said the West Bank-based Palestinian Authority received from Israel last week.The restrictions on lumber follow the doubling over the past several weeks of the number of truckloads of goods that Israel allows into the Gaza Strip through its only commercial crossing with the enclave.A Palestinian Authority liaison committee that coordinates those shipments said about 600 truckloads of food, fuel and cement for construction projects run by international agencies and a home-building initiative by Qatar were now being transferred daily.In the past six months, Israel has allowed 68,000 tons of cement into the enclave, said Gaza economist Maher al-Tabbaa, a spokesman for the local chamber of commerce. He said that was a fraction of what was required to meet reconstruction needs."Gaza needs a thousand tons of cement a day in order to be able to have a real rebuilding and development process," he said, accusing Israel of waging "economic warfare."Israeli officials said Hamas used cement and wood to buttress tunnels it dug under the border with Israel and that the militant group began reconstructing and repairing them soon after the war ended.