Prime Minister Justin Trudeau and Quebec Premier Philippe Couillard both characterised the attack as a terrorist act, which came amid heightened tensions worldwide over Trump’s travel ban on seven Muslim countries.

Trudeau said in Parliament the victims were targeted simply because of their religion and spoke directly to the more than 1 million Muslims who live in Canada, saying, “We are with you.”

“Thirty-six million hearts are breaking with yours,” Trudeau said. “Know that we value you.”

The suspect was arrested in his car on a bridge near d’Orleans, where he called 911 to say he wanted to cooperate with police. Authorities, who initially named two suspects, said the other man taken into custody was a witness to the attack and was released earlier Monday. They said they did not believe there were other suspects but were investigating.

Police did not give a motive for the attack.

Trump called Trudeau to express condolences to the Canadian people and to offer any assistance that might be needed.

The White House pointed to the attack as an example of why Trump’s policies were needed. “We condemn this attack in the strongest possible terms. It’s a terrible reminder of why we must remain vigilant and why the president is taking steps to be pro-active, rather than reactive when it comes to our nation’s safety and security,” White House spokesman Sean Spicer said.

The victims were businessmen, a university professor and others who had gathered for evening prayers, said Mohamed Labidi, the vice president of the mosque.

“’It’s a very, very big tragedy for us,” Labidi said tearfully. “We have a sadness we cannot express.”

He said the victims were shot in the back. “Security at our mosque was our major, major concern,” he said. “But we were caught off guard.”

The shooting took place just before 8pm Sunday. Witnesses described chaos as worshippers scrambled to find friends and loved ones, as police responding to the scene called for backup.

Canada is generally welcoming toward immigrants and all religions, but the French-speaking province of Quebec has had a long-simmering debate about race and religious accommodation. The previous separatist government of the province called for a ban on ostentatious religious symbols, such as the hijab, in public institutions.

Couillard said he would “not go there” when asked if he blamed recent rhetoric in the US for the attack.

“Quebec is a good, generally loving society, but we have these devils as other societies have. We have to recognise that and fight them,” Couillard said at a news conference in Quebec City at which he and Muslim leaders held hands in a display of solidarity.

“The Muslim community was the target of this murderous attack,” Couillard said, adding that solidarity rallies would be held across Quebec later Monday.

The mosque has been a target of hate crimes in the past, including last summer when pig’s head was left on its doorstep during Ramadan, when Muslims fast from dawn to sunset. Practicing Muslims do not eat pork.

Quebec City Mayor Regis Labeaume, appearing shaken, said: “No person should have to pay with their life, for their race, their color, their sexual orientation or their religious beliefs.”

Worshipper Ali Hamadi said he left the mosque a few minutes before the shooting and a friend, Abdelkrim Hassen, was killed. He said Hassen, who worked in information technology for the government, had three daughters and a wife, whom he had to notify of the death.

Majdi Dridi of the Muslim Association of Canada said he knew two of the victims. One was a work colleague who was a father of three little girls, he said.

“I don’t know what to say, I just hope that his family and his children can have the patience to accept what happened,” Dridi said

Trudeau had earlier reacted to Trump’s visa ban for people from some Muslim-majority countries by tweeting Saturday: “To those fleeing persecution, terror & war, Canadians will welcome you, regardless of your faith. Diversity is our strength #WelcomeToCanada.”

Trudeau also posted a picture of himself greeting a Syrian child at Toronto’s airport in late 2015. Trudeau oversaw the arrival of more than 39,000 Syrian refugees soon after he was elected.

The mayor of Gatineau, Quebec, near Canada’s capital of Ottawa, said there would be an increased police presence at mosques around his city following the attack. The New York Police Department also said it was stepping up patrols at mosques and other houses of worship.