On Tuesday police arrested 37 Palestinian teenage workers, ages 16-17, who had entered into Israel illegally and established a makeshift camp near the Dror Interchange north of Ra'anana. At the site there were mattresses, food, and blankets, indicating a semi-permanent encampment, police said. Police have sought to crack down on the phenomenon of illegal workers in Israel, after a string of terrorist attacks were perpetrated by Palestinians who illegally entered Israel. However, human rights groups including the left-wing B'Tselem - The Israeli Information Center for Human Rights in the Occupied Territories - contend that undocumented Palestinian workers, most of whom enter Israel for economic reasons, are being unduly punished.