Iraqis shop at the start of the holy month of Ramadan, in Baghdad, Sept. 23, 2006

Muslims around the world are beginning to mark the start of the holy month of Ramadan.

Palestinians in the West Bank town of Ramallah flocked to markets Saturday to buy groceries in preparation for the Islamic calendar's holiest month.  Ramadan commemorates the time when it is believed that the words of the Muslim holy book, the Koran, were revealed to the Prophet Mohammed more than 1,400 years ago.

In Iraq, Sunni Muslims began observing the event after announcing the sighting of the new moon, while for Shi'ites, the month is expected to start on Sunday or Monday.

The American-based Islamic Relief organization encouraged Muslims around the world to increase their charitable deeds.  It said the international aid group expects to provide more than 1 million people in 25 countries with food packs during the holy month.

President Bush said in a statement released Friday that Ramadan was an opportunity for Muslims to gather with family and friends and to show thanks for God's blessing.

During the holy month, Muslims are forbidden to eat, drink, smoke and have sexual activity in daylight hours.  Family and friends often gather at sundown to break their daily fast with a feast called "iftar."