Israel closed off all crossing points with the West Bank for Yom Kippur, the holiest day in the Jewish calendar. The army said in a statement that all crossings would remain closed until Saturday evening due to the festival, which starts at sundown on Friday, though exceptions could be made for people who needed medical attention. Israel systematically closes crossing points with the West Bank on its main holidays, for fear of attacks. The Gaza Strip, run by the Islamist Hamas movement since June 2007, is shut down even more tightly. Yom Kippur is devoted to prayer and fasting. During the festival air traffic, public transport and radio and television programmes are completely cut off.