Saudi Arabia and the United Arab Emirates (UAE) are shortening the traditional Friday prayers due to intense heat, until the end of the summer.
In many countries, Muslims perform the Friday noon prayers, which include a religious sermon, in open-air arenas inside and outside the mosques.
The UAE directed all the preachers across the country to limit the Friday prayers to 10 minutes until early October "to ensure the safety of worshippers."
In Saudi Arabia, Friday prayers at the Grand Mosque in Mecca and the Prophet's Mosque in Medina are being limited to 15 minutes, to take into account worshippers praying in outer, unshaded areas, the Presidency of Religious Affairs said.
Meanwhile in Iraq, influential cleric Muqtada al-Sadr urged preachers to "adhere to simple prayers" in order to keep the Friday sermon short, so that worshippers avoid intense heat.
Intense heatwaves have affected people across the Middle East in recent weeks.
More than 1,300 Muslim pilgrims died in the annual Hajj pilgrimage that ended earlier in June amid the extreme heat.