Pictured: Muslim pilgrims pray in Mecca as annual Hajj begins

In sweltering temperatures, Muslim pilgrims in Mecca converged on a vast tent camp in the desert on Friday, officially opening the annual Hajj pilgrimage.

Ahead of their trip, they circled the cube-shaped Kaaba in the Grand Mosque, Islam’s holiest site.

More than 1.5 million pilgrims from around the world have already amassed in and around Mecca for the Hajj, and the number was still growing as more pilgrims from inside Saudi Arabia joined. Saudi authorities expected the number to exceed 2 million this year.

This year’s Hajj came against the backdrop of the raging war in the Gaza Strip between Israel and Palestinian militants, which pushed the Middle East to the brink of a regional war between Israel and its allies on one side and Iran-backed militant groups on the other.

Palestinians in the coastal enclave of Gaza were not able to travel to Mecca for Hajj this year because of the closure of the Rafah crossing in May when Israel extended its ground offensive to the strip’s southern city of Rafah on the border with Egypt.

This year’s Hajj also saw Syrian pilgrims traveling to Mecca on direct flights from Damascus for the first time in more than a decade.

The change is part of an ongoing thaw in relations between conflict-stricken Syria and Saudi Arabia. Syrians in rebel-held areas used to cross the border into neighboring Turkey in their exhausting trip to Mecca for Hajj.

“This is the natural thing: Pilgrims go to Hajj directly from their home countries,” said Abdel-Aziz al-Ashqar, a Syrian coordinator of the group of pilgrims who left Damascus this year for Hajj.

The pilgrimage is one of the Five Pillars of Islam, and all Muslims are required to make the five-day Hajj at least once in their lives if they are physically and financially able to do so.