Around two million Muslim pilgrims congregated at Arafat outside Makkah on Wednesday, many of them praying for peace in the Middle East countries ravaged by war and chaos as the annual Haj reached its climax.

Haj is a duty for all Muslims at least once in their lives if they can afford it, and for many of the faith's 1.6 billion adherents it represents a moment of supreme spiritual worth that was reflected in the joy expressed at Arafat.

The pilgrims packed should-to-shoulder for an emotional day of repentance and supplication. Many wept as they raised their hands toward the sky, asking for forgiveness and praying for loved ones.

Throughout the day, hundreds of thousands of pilgrims scaled the hill and prayed facing the Kaaba, the cube-shaped structure in Makka that observant Muslims around the world face in prayer five times a day.

In the same day, pilgrims replaced the covering of the Kaaba with a new one, a custom done every year during pilgrimage, the official Saudi Press Agency (SPA) reported.

Mount Arafat is about 20 km east of Makkah.

"I wish everyone could come here. I am sure they would leave with a good heart because here Islam was born," said Abdullah, a Chinese convert to Islam.

The rocky areas of Arafat, Mina and Muzdalifah a few kilometres east of Makkah are the main sites of Haj, which culminates with Thursday's Eid Al-Adha holiday.

As early as Tuesday night, thousands of pilgrims left the haj camp at Mina and started climbing the low, rocky Mount Arafat where they will remain until sunset on Wednesday.

One old woman crawled up its steep slopes on hands and knees. Others scrawled their names on the rocks with pen to mark their presence.

But along with joy, many pilgrims also felt sadness and anger as the woes of the Muslim world weighed heavy on their minds.

EXTREME SUMMER HEAT

Over breakfast, a group of pilgrims from different countries quizzed an Iraqi man who had fled an area controlled by the Islamic State militant group, which has seized swathes of Iraq and Syria and staged attacks elsewhere.

"Islam is mercy. How did they turn it into a curse, a punishment?" said one man.

Earlier, in the city of Mecca, a Yemeni pilgrim said he hoped peace might soon return to his country, where a Saudi-led Arab coalition this year joined the government's side in a civil war that has killed thousands, including by its own airstrikes.

"I have a million wishes. The first and the last is to have the happy Yemen back: the free and united Yemen," he said.

A Syrian pilgrim simply called down curses on President Bashar Al-Assad, who is waging a war to end a four-year rebellion against his rule. "Bashar goes to hell," was his wish.

But pilgrims also prayed for personal matters. Abdullah, the Chinese pilgrim, expressed his hopes for the coming year.

"I wish my wife heals from her sickness, my son finishes school and my manager gives me the promotion I deserve," he said.

In the extreme summer heat, even early in the morning, many pilgrims clutched bottles of water or held umbrellas over their heads as they stood at Arafat.

Later on Wednesday they will descend to the plain of Muzdalifah where they will collect pebbles to "stone the devil" at a rite on Thursday. - Reuters