More than 1,000 pilgrims have died in Saudi Arabia during Hajj this year. Scorching heat continues in MeccaThousands of people were also being treated for heatstroke as temperatures in Mecca reached 49 degrees Celsius (120 degrees Fahrenheit), AFP reported.

More than half of those killed were unregistered pilgrims. According to an Arab diplomat, about 658 pilgrims from Egypt have been killed. Of these, 630 were unregistered pilgrims.

according to sources, 90 deaths were from IndiaThere are reports of deaths of pilgrims in Jordan, Indonesia, Iran, Senegal and Tunisia also.

Several pilgrims were also reported missing, and Facebook and other social media networks were flooded with requests for information and photographs of the missing.

More than 1.8 million people are taking part in the Hajj this year, one of the world’s largest religious gatherings, according to the Saudi government.

As a precautionary measure, Hajj authorities have asked pilgrims to carry umbrellas and stay hydrated. The Saudi military has deployed more than 1,600 personnel and 30 rapid response teams along with medical units to care for heatstroke victims, CNN reports. In addition, 5,000 health and first aid volunteers have also been deployed.

Only 240 pilgrims were reported dead last year, most of them Indonesians.

On Monday, the National Meteorological Center recorded a maximum temperature of 51.8 degrees Celsius at Mecca’s Grand Mosque. Studies have shown that temperatures in the region are rising by 0.4 degrees Celsius every decade.