Israeli tanks backed by helicopters searched Monday for Palestinian activists in the Jenin refugee camp in the West Bank. Israeli troops searched from house to house as two helicopters hovered in the sky overhead, witnesses said. Exchanges of fire erupted between Palestinians and soldiers, Army Radio reported. The army has been positioned around the camp, imposing a curfew on its residents. Palestinian sources reported in the afternoon that Israeli special forces in Jenin arrested the most wanted Hamas man in the West Bank, Sheikh Jamal Abu el Hija, 44. According to the sources, the Israelis detained Sheikh Abu el Hija...