Muslims around the world are observing the holy month of Ramadan, while sweltering heat in the Middle East is putting an extra strain on those who are fasting.
Ramadan started earlier than usual this year, although there is some disagreement between the two main sects of Islam on the exact starting date.
Sunni Muslims began fasting at dawn Wednesday, while Shi'ites are expected to start Thursday. The discrepancy is due to differing interpretations of the lunar calendar.
High heat across much of the Arab world has raised concerns for families, particularly in places like Baghdad and the Gaza Strip, where electricity is routinely cut off for hours at a time.
To mark the month of Ramadan, U.S. President Barack Obama and his wife, Michelle, extended best wishes to Muslims in the United States and around the world.
Mr. Obama's office issued a statement Wednesday noting that Ramadan is a time when Muslims reflect on the wisdom and guidance that comes with faith, and on the responsibility that people have to each other and to God. He said he looks forward to hosting a traditional "iftar" dinner celebrating Ramadan at the White House later this week.
During Ramadan, observers refrain from eating, drinking and sex between daybreak and sunset.
The month of Ramadan marks the time more than 1,400 years ago when Muslims believe the words of Islam's holy book, the Koran, were revealed to the Prophet Muhammad. Muslims celebrate the month with family visits and invitations to iftars, shared meals that break the fast. Ramadan will conclude in September with a celebration called Eid al-Fitr.