Canadian authorities say a 27-year-old man was solely responsible for the armed attack on a Quebec City mosque on Sunday.

The man, who has been identified as Alexandre Bissonnette, faces 11 charges: six counts of murder and five counts of attempted murder. In a brief appearance in court he did not enter a plea.

The Associated Press, citing local hospital officials, reports five shooting victims remain in critical condition and 12 others suffered minor injuries.

Local authorities initially were looking for two suspects, but another man arrested at the mosque was determined to be just a witness to the shooting, which occurred Sunday evening.

The police have not discussed a possible motive for the attack. The New York Times reports that Bissonnette has a history of anti-Islam comments online and had expressed support for the far-right French political party, the National Front.

According to Canadian news website TVA, a Facebook page reportedly belonging to Bissonnette included “likes” for Donald Trump and Marine Le Pen, the far-right French presidential candidate.

Canadian Prime Minister Justin Trudeau and Quebec Province Premier Philippe Couillard quickly called the shootings an act of terrorism.

U.S. President Trump called Canadian Prime Minister Trudeau to express his condolences. In a telegram, Russian President Vladimir Putin did the same.

Canada is generally welcoming towards immigrants and refugees, but tensions have been simmering in Francophone Quebec over attitudes towards Islam, The Telegraph reports.