After arriving in Quebec, Pope Francis met on Wednesday with Canada's political leaders, a largely diplomatic pause from the main purpose of his trip - apologizing for the Church's role in running residential schools where abuse was rife.

Arriving in Quebec's capital city on the fourth day of his Canadian tour, the pontiff sat in a wheelchair and smiled as he was greeted on the tarmac by indigenous representatives and political leaders.

As the pope's convoy drove from the airport to the city, many gathered along the road or on their lawns to catch a glimpse of the pontiff as he passed.

The pope was greeted at the Citadelle, which sits on the banks of the St Lawrence River, by Canada's head of state and prime minister and a long line of an honor guard wearing red uniforms and black bearskin caps.

The Citadelle de Quebec is the largest British fortress built in North America. It overlooks a park called the Plains of Abraham, where the pope's address to dignitaries will be broadcast later. It is also one of the official residences of Canada's governor general, Mary Simon, who is the representative of Queen Elizabeth, the head of state.

The pontiff first met with Simon, who is the first indigenous person to serve as governor general. Then Prime Minister Justin Trudeau, who has made reconciliation with Canada's indigenous peoples one of his political priorities, will speak privately with Francis.

The pope will speak publicly to officials, diplomats and indigenous leaders after the private meetings.

Marilyne Chachai-Piche, 26, led a march of 13 people who walked from Mashteuiatsh, an aboriginal Innu community, 266 km (165 miles) to Quebec City for the pope's visit.

"My mother was always told in the residential school: 'You don't have the right to speak your language'... She was told her skin color was bad for Christianity," Chachai-Piche said.

"I still live with the suffering."

On Tuesday, the pope presided over an open-air Mass in a football stadium while seated because of a knee ailment that has forced him to use a wheelchair on the trip. Later, he visited Lac Ste. Anne, a pilgrimage site popular with both indigenous Canadian Catholics and those of European origin.

There, he said the Roman Catholic Church should accept institutional blame for the harm done to indigenous Canadians in residential schools that tried to wipe out native cultures. [L1N2Z71BZ]

During his first full day in Canada on Monday, the pope traveled to the town of Maskwacis, site of two former schools, and issued a historic apology that called the Church's role in the schools, and the forced cultural assimilation they attempted, a "deplorable evil" and "disastrous error".

More than 150,000 indigenous children were separated from their families and brought to residential schools over the years. Many were starved or beaten for speaking their native languages and sexually abused in a system that Canada's Truth and Reconciliation Commission called "cultural genocide".

On Thursday, Francis will visit the Sanctuary of Sainte-Anne-de-Beaupre, the oldest Catholic pilgrimage site in North America, and meet the archbishop of Quebec, Canada's largely French-speaking province, in the Notre-Dame de Quebec Cathedral.

On his way back to Rome on Friday, he will stop for a few hours in Iqaluit in the Canadian Arctic, where indigenous issues will return to the fore.

(Writing by Steve Scherer, additional reporting by Anna Mehler Paperny; Editing by Deepa Babington)