Quebec provincial police now say only one of the two men arrested Sunday night following the deadly shooting at a Quebec City mosque is a suspect in the attack. 

The suspect, Alexandre Bissonnette, 27, appeared in court late Monday afternoon and was charged with six counts of first-degree murder and five counts of attempted murder while using a restricted firearm.

He is expected back in court Feb. 21.

In a pair of tweets sent shortly after noon, the Sûreté du Québec confirmed one of the men arrested is now considered a witness.

Six men died in the shooting shortly before 8 p.m. during evening prayers at the Centre Culturel Islamique de Québec (Islamic cultural centre of Quebec). Nineteen people were also wounded.

Police said it's too early to know the motive.

Witness mistakenly arrested

One of the men was arrested outside the mosque within minutes of the shooting. He was later released as a witness.

He spoke to CBC's French-language network, Radio-Canada, under the condition of anonymity and said he was outside the mosque, shovelling its steps, when he heard shooting.

After the shooting stopped, he went inside and called 911.

"I found [a victim] near the door. I didn't know if he was alive or dead," he said. 

"When I gave him my jacket to keep warm, I saw the image of someone with a firearm, I didn't know it was police. I thought it was a shooter who'd returned." 

He fled the scene but was arrested. He wasn't released until Monday.

At a police briefing Monday morning, Quebec City police Insp. Denis Turcotte said another man called 911 at 8:10 p.m. Sunday — 25 minutes after the shooting. That man told them he was armed and had been involved in the shooting.

"He seemed to want to co-operate," Turcotte said. The man told police he was parked near the bridge on Île d'Orléans, where he was arrested without incident.

Police Sgt. Christine Coulombe said the men who were killed ranged in age from 35 to 70. 

Five people are still in hospital. Two will need more surgery, while the other three are stable and may be discharged soon. Another 14 people have been released, according to a hospital spokeswoman.

Thirty-nine people escaped the mosque without injuries.

An act of terrorism, premier says

Quebec Premier Philippe Couillard called the shooting an act of terrorism.

"It's a murderous act directed at a specific community," he said at a news conference. "I think the majority of citizens — not just in Quebec, but elsewhere — would describe it that way."

Couillard also shared a message of solidarity with Quebec's Muslim community. "We are with you. You are at home. And you are welcome at home," he said. 

Prime Minister Justin Trudeau described the shooting as a "terrorist attack on Muslims in a centre of worship and refuge."

"Muslim-Canadians are an important part of our national fabric, and these senseless acts have no place in our communities, cities and country," said Trudeau in a statement.

Late Monday morning, Quebec City Mayor Régis Labeaume and Couillard held a news conference and invited several leaders from the Muslim community to speak.

Many had trouble getting through their prepared remarks, breaking down at the thought of the lives lost and the show of support they say their community has received since Sunday night.

Attack on the ground floor

Police said prayers were underway at the mosque when shots were fired just before 8 p.m. Men were praying on the ground floor of the building, while women and children were upstairs.

CANADA-MOSQUE/SHOOTING

Quebec City police said they are working with the RCMP and the Quebec provincial police following the shooting at a Quebec City mosque that left six people dead and 19 wounded. (Mathieu Belanger/Reuters)

Quebec City police deployed all available officers, Turcotte said.

CANADA-MOSQUE/SHOOTING

Some of the wounded were in critical condition. (Mathieu Belanger/Reuters)

By 10:40 p.m., police said the situation was under control. 

"The building is secure and the occupants evacuated. The investigation continues," tweeted Quebec City police, who are working with the RCMP and provincial police.

CANADA-MOSQUE/SHOOTING

Police patrolled the perimeter near the mosque after the shooting. (Mathieu Belanger/Reuters)

Suspect a Laval student

The suspected shooter, Bissonnette, studied anthropology and political science at Laval University, according to his Facebook page, which was taken down on Monday.

Police stepped up patrols at the university, as well as at other mosques in Quebec City and elsewhere in Quebec.

Police erected perimeters and road blocks in other areas of Quebec City as part of their investigation. A search was also underway at a home in Sainte-Foy.

'A Québécois accent'

Last night, shortly after the shooting, a witness who asked to remain anonymous told Radio-Canada that two masked individuals entered the mosque. 

"It seemed to me that they had a Québécois accent. They started to fire, and as they shot, they yelled, 'Allahu akbar!' The bullets hit people that were praying. People who were praying lost their lives. A bullet passed right over my head.

"There were even kids. There was even a three-year-old who was with his father," the witness said. 

The latest information from provincial police, however, is that there was only one shooter.

Canadian Press Map

A few dozen people were inside the Islamic cultural centre of Quebec in the Sainte-Foy neighbourhood when the shooting began just after 8 p.m. (Canadian Press)

Call for solidarity with Muslims

Mayor Labeaume fought back tears during a news conference early Monday, saying the city is in mourning. 

"To the Muslim community, our neighbours, our co-citizens, who count on our support and solidarity, I want to say, 'We love you,'" he said. 

Quebec Mosque Shooting 20170129

People outside the mosque paid their respects. Martin St. Louis holds a sign that reads, 'La paix non la guerre,' which means 'peace, not war.' (Francis Vachon/Canadian Press)

Politicians around the world also denounced the attack.

A message on the Facebook page of the mosque's administration said: "Thank you for the hundreds of compassionate messages coming from everywhere."

Politicians and community leaders will attend a vigil in Quebec City on Monday evening. Other ceremonies have been planned across the country.

Officer Quebec city mosque shooting

According to Quebec City police, the shooting began just before 8 p.m. ET. (Maxime Corneau/Radio-Canada)

The mosque was previously the target of vandals. Last June, during the Muslim holy month of Ramadan, a pig's head was left on its doorstep.

Quebec City police Chief Robert Pigeon said Monday that police had not established any link between the pig's head incident and Sunday night's shooting.

Authorities are asking anyone with information into Sunday's attack to contact Quebec provincial police at 1-800-659-4264.

With files from Radio-Canada