Israeli security forces frequently beat Palestinians working illegally in the country, sometimes severely, and detain them for hours without food and water, the human rights group B'Tselem said in a report published Tuesday. Security officials said in response to the report that the troops were operating under tough conditions to prevent Palestinian suicide bombers from infiltrating the country. Any abuse allegations are investigated, the officials said. Each week, security forces catch thousands of West Bank Palestinians sneaking into Israel through holes in Israel's uncompleted separation barrier, human rights groups say. With unemployment in the West Bank running at approximately 25 percent, workers have grown more desperate to cross. While Israel used to permit tens of thousands of Palestinian laborers into the country, it has sharply reduced that number during the past six years of violence. Israel says the barrier, whose more than 600-kilometer route is roughly two-thirds complete, is needed to protect the country against suicide bombers. Workers sneaking into Israel are frequently detained by border police for much longer than the few hours allowed by Israeli law, often in the hot sun or rain without food or water, said Eitan Diamond, a B'Tselem researcher. The detention appears to be used as a form of punishment, since the workers are usually not thrown in jail due to overcrowding, Diamond said. In interviews with dozens of workers, B'Tselem found that beatings are common, the report said. "Every worker we talked to told us that at least once they were beaten, and sometimes severely," Diamond said. "There is a constant fear of a clash with the border police." There have been some well-publicized incidents of Israeli security forces shooting and killing illegal Palestinian workers. In two such cases last year, indictments were issued against border policemen. But many instances of abuse are never revealed, B'Tselem said. The IDF said its forces were trying to thwart frequent infiltration attempts by suicide bombers and tries to operate without opening fire. The army investigates instances in which soldiers are accused of abusing their power, the army said. The Justice Ministry, which investigates complaints against border police, said many cases are closed due to lack of evidence, but several have resulted in indictments.