More than 1.5 million Muslim pilgrims gathered in Mina, a valley southeast of the holy city of Makkah in Saudi Arabia, on Wednesday to perform the symbolic stoning of the devil — the climactic ritual of the annual Haj pilgrimage, which this year coincides with the festival of Eid al-Adha.

From dawn, pilgrims moved through Mina's vast tent city carrying pebbles collected overnight at Muzdalifah, a plain that lies halfway between Mount Arafat and Mina. Each pilgrim threw seven stones at each of three large concrete pillars representing the devil, re-enacting the story of the Prophet Ibrahim, who according to Islamic tradition resisted Satan's attempts to stop him from obeying God's command to sacrifice his son Ismail at three separate locations. After completing the stoning, many male pilgrims shaved their heads while women cut a small portion of their hair, marking the formal conclusion of the Haj rites. Many pilgrims also carried out animal sacrifices in keeping with Eid al-Adha observance. The pilgrims then return to Makkah for a final circumambulation of the Kaaba, the cube-shaped structure at the centre of the Grand Mosque regarded as the holiest site in Islam.

The day before, pilgrims had stood in prayer atop Mount Arafat — the site where the Prophet Mohammed is believed to have delivered his final sermon — enduring temperatures of 45°C before spending the night under the stars at Muzdalifah to collect their pebbles. Saudi authorities deployed extensive security and crowd management measures throughout the day, one of the busiest of the entire pilgrimage season.

This year's Haj, in which a total of around 1.7 million people are taking part, is unfolding for the third consecutive year under the shadow of regional conflict. An ongoing US-Israeli confrontation with Iran, which has drawn in Gulf nations, has cast a pall over the gathering, though a fragile ceasefire in place since 8 April has largely halted active fighting. Diplomatic efforts to reach a definitive end to the conflict have so far yielded no conclusive outcome.

The Haj, one of the five pillars of Islam, is an obligation for every Muslim who is physically and financially able to undertake it at least once in a lifetime. Its rituals draw pilgrims from across the world to the same locations over the same days each year, making it one of the largest annual human gatherings on earth.