RIYADH — For Muslims in Saudi Arabia and most Sunni-ruled Middle Eastern states Ramadan will begin on Saturday, but in Shiite-majority Iran and Iraq it will start the following day, authorities announced.

The holy month, during which hundreds of millions of faithful around the world observe a daytime fast, traditionally begins with the sighting of the crescent moon.

Sunni-majority Saudi Arabia, home to Islam’s two holiest sites, was joined by its Gulf Arab neighbors in declaring that the moon had been sighted on Friday.

“The Supreme Court has decided that tomorrow, Saturday, is the first day of the month of (Ramadan),” the official Saudi Press Agency posted on X.

Algeria, Egypt, Jordan, Libya, the Palestinian territories, Sudan and Tunisia announced they too would begin the daytime fast on Saturday.

But the office of Iran’s supreme leader, Ayatollah Ali Khamenei, and Iraq’s top Shiite cleric, Ayatollah Ali al-Sistani, declared Sunday the first day of Ramadan.

Only in Morocco, at the far-western edge of the Arab world, will Sunnis start observing the daytime fast on Sunday, its Islamic affairs ministry announced.

In multi-confessional Lebanon, the grand mufti announced Saturday as the first day of Ramadan for Sunnis, state media reported.

Observing the Ramadan fast is one of the five pillars of Islam, requiring believers to abstain from eating, drinking, smoking and sex during daylight hours. Observant Muslims are also encouraged to donate to the poor.