Much of the world's estimated 1.6 billion Muslims will start observing the holy month of Ramadan on June 29.
The Muslim holy month is marked by daily fasting from dawn to sunset.
It ends with the Islamic holiday of Eid al-Fitr.
Saudi King Abdullah, in a Ramadan message on June 28, vowed to crush Islamist militants threatening the kingdom.
The remarks came two days after the monarch ordered all necessary measures to protect the country against potential "terrorist threats" resulting from turmoil in neighboring Iraq.
Saudi Arabia shares an 800-kilometer border with Iraq.
The birthplace of Islam, it sees itself as a champion of pure Sunni Muslim values and regards Shi'ite Iran as its main regional foe.
Based on reporting by AP and Reuters