MOUNT ARAFAT: In his annual Haj sermon on Friday, Saudi Arabia’s top religious figure termed the extremist Islamic State militants as Khawarijites and the enemies of humanity.

Addressing millions of Muslims from around the world gathered in Makkah for the Haj, the Grand Mufti of the Ka'aba Sheikh Abdulaziz al-Sheikh said that conspiracies were being hatched against Muslims, and that some movements in the Muslim world were enemies of humanity.

He urged Muslims around the world to avoid sectarianism, which he said was weakening the religion. Referring to acts to terrorism by extremist militants, he warned believers against the spilling of innocent blood.

This year's Haj comes with Saudi Arabia and four other Arab nations joining Washington in air strikes against Islamic State group militants who have committed a spate of atrocities in Syrian and Iraqi territory they seized.

Tears flowed and prayers filled the air as close to two million believers from around the world reached the vast plain of Mount Arafat in western Saudi Arabia.

“I am now a newborn baby and I don't have any sin,” Nigerian pilgrim Taofik Odunewu told news agency AFP, standing at the foot of Mount Mercy on the Arafat plain, tears streaming down his face.

Odunewu raised his hands to the heavens in the seamless two-piece white “ihram” outfit that he wore.

“I pray for prosperity, long life and.. I pray for my country,” Odunewu said with a broad smile.

“I'm very blessed to be part of this occasion. I don't think I will go back to the sinful way,” he pledged.

The Haj, which officially ends on Tuesday, is the world's largest Muslim gathering.

It is one of the five pillars of Islam that every capable Muslim must perform at least once, the high-point of his or her spiritual life.

Hundreds of thousands of pilgrims arrived at Arafat on Friday carrying suitcases and other luggage among thousands of white tents which stood ready to accommodate the multitude.

From early morning, pilgrims crowded onto the slippery, rocky hill known as Mount Mercy, where the Holy Prophet Mohammed (Peace Be Upon Him) made his final sermon 14 centuries ago.

The pilgrims' attire turned the hill white in colour, and they carried umbrellas as shields against the hot desert sun.

All male pilgrims dress in white ihram to symbolise a state of purity, which also emphasises their unity regardless of social status or nationality.

Some pilgrims sat alone on rocks, praying silently, as others gathered in groups, their voices in a loud appeal to God.

Egyptian pilgrim Mohammed Ahmed, 53, sat with his wife under a yellow bag they set up as a make-shift tent.

He said they were praying for “the victory of Muslims, those who are weak, oppressed, and jailed... all over the world.”

Almost 1.4 million foreign pilgrims from 163 nations

Saudi Interior Minister Prince Mohammed bin Nayef said the hajj had attracted almost 1.4 million foreign pilgrims from 163 nations.

Local media report that several hundred thousand Saudis are also participating, pushing the total towards two million.

Security forces were deployed en masse across Arafat plain and Mount Mercy to organise the wave of humanity.

“This way, hajji. Don't stop here. You're blocking the way,” security men shouted through loudspeakers, trying to control the crowds.

“Sometimes we have difficulties understanding each others' languages, and mostly the elderly can't understand what we are saying,” said Ali al-Shemmari, a soldier stationed at the hill.

“The pilgrims believe that they should climb up, although this is not necessary... But things are going well,” he said.

Crackdown on illegal pilgrims

The number of faithful seemed fewer than past years following a crackdown by authorities on illegal pilgrims, more than 145,000 of whom have been turned away, the official Saudi Press Agency said.

Permits are a way of ensuring that such a large gathering with massive logistical challenges proceeds smoothly.

AFP reporters said security appeared to have been stepped up, helping the crowds to flow more smoothly than in past years.

Saudi authorities are also striving to protect pilgrims from two deadly viruses, Ebola and the MERS coronavirus.

No such cases have been recorded among the hajj visitors, officials say.

Odunewu and other pilgrims from Nigeria were permitted to enter Saudi Arabia for Haj, despite eight Ebola deaths in their country, but three West African states hardest hit by Ebola have not been allowed Haj visas.

Pilgrims will stay at Mount Arafat until sunset when they set off for nearby Muzdalifah, where they gather pebbles for the symbolic “stoning of the devil” on Saturday.

In conjunction, animals will be slaughtered for Eidul Azha, the feast of sacrifice celebrated by Muslims worldwide.