The Muslim fasting month of Ramadan will start on Monday in Saudi Arabia, media reports said.
The new moon of Ramadan was not spotted Saturday (May 5) evening and therefore Sunday will mark the last day of the Islamic month of Shaaban, the broadcasters added, citing religious authorities in the monarchy.
The beginning and end of Hizri months are determined by the sighting of the new moon.
Kuwait, another Gulf country, also announced that Monday will be the first day of Ramadan.
During Ramadan, Muslims have to abstain from eating, drinking and smoking from dawn to sunset.
Devout Muslims also mark the holy month by intense worship, performing special nightly prayers and reading Islam's holy book, Al Quran.
Fasting is one of Islam's five pillars, alongside the declaration of monotheism, prayer five times a day, alms-giving, and pilgrimage to holy sites in Saudi Arabia.