This year's Ramadan comes on the heal of the relocation of the US Embassy to Jerusalem, an occupied city that is holy to the three Abrahamic faiths.
On Monday, Saudi Press Agency (SPA) urged all Muslims throughout the Kingdom of Saudi Arabia to keep a lookout for the crescent on Tuesday evening, Sha'ban 29, 1439H, which corresponds to May 15, 2018 in the Gregorian calendar.
Saudi Arabian moon observers said there was no sight of the Ramadan crescent on Tuesday, meaning millions of Muslims around the world will begin the holy month on Thursday.
Oman was the first country in the Gulf to announce when it will mark the beginning of Ramadan.More news: Fulham take a step closer to EPL promotion
Ramadan is the ninth month of the Islamic calendar and considered as the holiest month of the year by Muslims.
The American Human Rights Council (AHRC-USA) board of directors, staff and volunteers extend their greetings to all Muslims on the occasion of the holy month of Ramadan. Those observing refrain from food or drink from sun-up to sundown, with exceptions for age or health conditions, and break the day's fast with the iftar meal.
Announcing the timings of various services during the holy month, the Roads and Transport Authority (RTA) said from Saturday to Wednesday, the Metro service will be operational on both the lines from 5am to 12am.
Eid Al-Fitr, or "the feast of breaking the fast", is a three-day religious holiday marking the end of Ramadan, which is celebrated by Muslims worldwide.