Watch: Muslim worshippers gather for Friday prayers in Mecca during Ramadan

Watch as Muslim worshippers gathered for prayers in Mecca on Friday, 15 March during Ramadan.

The start of the holy fasting month of Ramadan began for many of the world's 1.8 billion Muslims on Sunday night when officials saw the crescent moon in Saudi Arabia, home to the holiest sites in Islam.

During the month, observers will abstain from food and water from dawn to sunset in a period of religious reflection.

Ramadan marks the ninth month of the Islamic calendar, during which Muslims believe the first verses of the Quran were revealed to the Prophet Muhammad.

Fasting is observed as it is one of the Five Pillars of Islam; other pillars are prayer five times a day, charity, profession of faith, and making the pilgrimage to Mecca once in a person's lifetime.

This year's Ramadan is occurring during Israel's ongoing war against Hamas in the Gaza Strip, where many Muslims are observing the holy month in war-damaged mosques.

Israeli attacks have damaged 260 mosques across the strip, reducing them to rubble, but Palestinians continue to pray in the courtyards and among the ruins of the holy sites.