Muslims around the world are marking the start of Ramadan, a month of intense prayer and dawn-to-dusk fasting. It is also a month of feasting, with families and friends gathering at sunset for 'Iftar', the meal eaten by Muslims to break the fast.
Muslims follow a lunar calendar and the sighting of the new moon can lead to different countries declaring the start of Ramadan a day or two apart. This year Saudi Arabia, Egypt, Iran, Indonesia and most other parts of the world announced that fasting would begin on Thursday. Pakistan declared that the first day of the holy month of Ramadan will be observed on Friday, subject to sighting of the new moon.
During Ramadan, observant Muslims abstain from eating and drinking from sunrise to sunset for the entire month. The fast is intended to bring the faithful closer to God and to remind them of the suffering of those less fortunate.
Muslims often give to charities during the month, and mosques and aid organisations arrange free meals for the public every night.
Those wishing to be polite to someone who is fasting for Ramadan may greet them with Ramadan Mubarak or Ramadan Kareem, which mean Have a Blessed or Generous Ramadan.
This year, Ramadan falls during the summer, which means long days of fasting. Mainstream scholars advise Muslims in northern European countries with 16 hours or more of daylight to follow the cycle of fasting of the nearest Muslim majority nation to them to avoid impossibly long hours without food or water.
Pia Jardi, chairwoman of the Finnish Muslim Union in Helsinki, said if Muslims there followed sunrise and sunset they would be fasting for 21 hours and have just three hours — or even less — for eating, drinking and prayer before the sun rises again.
Children, the elderly, the sick, women who are pregnant or menstruating and people travelling are not obligated to fast. Non-Muslims or adult Muslims not observing the fast who eat in public during the day in Ramadan can be fined or even jailed in some Middle Eastern countries, such as Saudi Arabia and the United Arab Emirates, home to large Western expatriate populations in Dubai and Abu Dhabi.
Fasting during Ramadan is one of the five pillars of Islam, along with the declaration of faith, daily prayer, charity and performing the hajj in Mecca.
The world's 1.6 billion Muslims traditionally break their fast like the Prophet Muhammad did around 1,400 years ago, with a sip of water and some dates at sunset. Then family and friends gather for a large feast. Part of the evening is often spent at the mosque in prayer.
Muslims celebrate the end of Ramadan with a three-day holiday called Eid al-Fitr.