"After taking into account the hisab [astronomical calculation] and rukyat [new moon observation] methods, we have determined that the first day of Ramadan this year will fall tomorrow on Friday," Religious Affairs Minister Fachrul Razi said.

He called on Muslims to refrain from attending religious gatherings or performing the tarawih (evening Ramadan prayers) in congregations during the COVID-19 outbreak to avoid the risk of contracting the disease.

"We also discourage ziarah [visiting relatives’ graves] and the Idul Fitri mudik [exodus], which could potentially spread the disease," the minister said, adding that those who fasted should pay attention to their nutritional intake to boost their immunity.

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The government’s decision to start Ramadan on Friday was endorsed by all major Islamic organizations, including the second-largest in the country, Muhammadiyah, which had for years set different dates for the start of the fasting month.

Muhammadiyah, which only uses the hisab method to determine when Ramadan begins, announced in late February that the fasting month would start on Friday, while Idul Fitri would fall on May 24.

Ramadan is expected to last for 30 days. The government will hold another isbat meeting in late May to determine the date of Idul Fitri.

Various Islamic groups in Indonesia use different methods to determine the start of Ramadan on the Islamic Hijriyah calendar, which is based on lunar observations.

For example, the An Nazir sect in Gowa, South Sulawesi, marked Thursday as day one of fasting after making calculations based on the highest tidal waves.

The Tareqat Naqsabandiyah in West Sumatra also started Ramadan on Thursday, as reported by local media outlets. It used the hisab-munjid method, a mixture of mathematical and astronomical calculations.