This year heat is unbearable throughout the world, and the death toll from this year's Hajj exceeded 1,000 on Thursday, with more than half of the deceased being unregistered worshippers who undertook the pilgrimage in extreme heat in Saudi Arabia.

The new deaths included 58 from Egypt, according to an Arab diplomat who provided a breakdown showing that out of 658 total deaths from that country, 630 were unregistered. The overall death toll stood at 1,081, with close to 70 Indians believed to have died.

The National Meteorological Centre in the country reported a high of 51.8 degrees Celsius earlier this week at the Grand Mosque in Mecca. According to a Saudi study published last month, temperatures in the area are rising by 0.4 degrees Celsius each decade.

Each year, tens of thousands of pilgrims attempt to perform the Hajj through irregular channels as they cannot afford the often costly official permits. Saudi authorities reported clearing hundreds of thousands of unregistered pilgrims from Mecca earlier this month, but it appears many still participated in the main rites which began last Friday.

This group was more vulnerable to the heat because, without official permits, they could not access air-conditioned spaces provided by Saudi authorities for the 1.8 million authorized pilgrims to cool down after hours of walking and praying outside.

One Arab diplomat told news agency AFP the principal cause of death among Egyptian pilgrims was the heat, which triggered complications related to high blood pressure and other issues. In addition to Egypt, fatalities have also been confirmed in Malaysia, Pakistan, India, Jordan, Indonesia, Iran, Senegal, Tunisia, and Iraq's autonomous Kurdistan region, though in many cases authorities have not specified the cause.

Several agencies reported that friends and family members have been searching for pilgrims who are still missing.