Israel tightens security in Jerusalem Old City as Ramadan begins Officials saw the crescent moon Sunday night in Saudi Arabia, home to the holiest sites in Islam, marking the start of the holy fasting month of Ramadan for many of the world's 1.8 billion Muslims. In Israel, authorities have tightened security in the old city of Jerusalem, a hot spot for clashes where the holiest site in Judaism and the third holiest site in Islam is housed, FRANCE 24's Andrew Hilliar said, reporting from Jerusalem.