The pontiff was greeted by thousands in a sports stadium in the Kurdistan region's capital Arbil who had gathered despite fears the event could become a Covid-19 "super-spreader".

The 84-year-old was driven in his white, windowless "pope-mobile" into the stadium, where jubilant worshippers sat socially distanced on white chairs spread out on the greens.

Others stood, craning their necks to catch a glimpse of Francis, in the stands ringing the Franso Hariri Stadium, named after an Iraqi Christian politician who was assassinated by extremists 20 years ago.

The faithful wore hats featuring pictures of Francis, and face-masks to protect them from Covid, as a second wave has driven up cases to around 5,000 new infections per day in Iraq.

The stadium seats around 20,000, but large swathes of the stands were empty after authorities had trimmed down the allowed attendance in recent days.

"It's a special trip, also because of the conditions," said Matteo Bruni, the Vatican's spokesman, who described the visit to Iraq as "a gesture of love for this land its people".

Iraq's Christian population has shrunk to fewer than 400,000, from around 1.5 million before the US-led invasion of 2003.

Arbil has been a place of refuge for many Christians who fled violence over the years, including the onslaught from 2014 by the Islamic State group.

The heaviest deployment of security personnel yet is protecting Francis in northern Iraq, on what is perhaps the riskiest day of his historic trip.

The city was targeted just weeks ago by a deadly rocket attack, the latest in a series of strikes blamed on pro-Iranian forces.

- 'The most beautiful day' -

The visit to the north embodies a cause close to the pope's heart: reaching out to Iraq's traumatised Christian community.

Watching from afar in 2014 as IS swept across the northern province of Nineveh, Pope Francis said at the time he was ready to come and meet the displaced and other victims of war in a show of solidarity.

He fulfilled that promise on Sunday, first visiting Mosul, the onetime bastion of the Islamic State group, still largely in ruins.

With the partially collapsed walls of the centuries-old Al-Tahera (Immaculate Conception) Church behind him, Francis pleaded for Christians in Iraq and the Middle East to stay in their homelands.

He said the "tragic" exodus of Christians "does incalculable harm not just to the individuals and communities concerned, but also to the society they leave behind".

Francis spoke to the faithful in the courtyard of the Al-Tahera Church, whose roof collapsed during fighting against IS in 2017. It is one of the oldest of at least 14 churches in Nineveh province that were destroyed by the jihadists.

The pope was driven around the historic Old City -- largely razed during the grinding fight to dislodge the jihadists -- in a golf cart.

"Today was the most beautiful day for us, being visited by the pope!" said Hala Raad, a Christian woman who had fled when IS seized Mosul but returned to see the pope.

"We hope to come back to Mosul in health and wellbeing. The most important thing is security -- we want stability."

- 'Do not lose hope!' -

The pontiff also held a prayer service in Qaraqosh, whose ancient church -- named Al-Tahera, like the one in Mosul -- was torched by the jihadists as they destroyed most of the town.

Residents of Qaraqosh have since rebuilt their homes with little government help and Al-Tahera too has been refurbished, its marble floors and internal colonnades buffed to host its most important guest yet.

Dressed in traditional embroidered robes, hundreds of the faithful -- who speak a modern dialect of Aramaic, the language spoken by Jesus Christ -- welcomed the pontiff with hymns and olive branches.

"Do not stop dreaming! Do not give up! Do not lose hope!" Francis urged those gathered. "Now is the time to rebuild and to start afresh."

Pope Francis's trip to Iraq as a "pilgrim of peace" aims to reassure the country's dwindling Christian community, but also to expand his dialogue with other religions.

On Saturday, the leader of the world's 1.3 billion Catholics met Iraq's top Shiite Muslim cleric, the reclusive Grand Ayatollah Ali Sistani, who agreed that Iraq's Christians should be able to live in "peace".