President Trump speaks during a breakfast with small-business leaders at the White House on Jan. 30. (Jabin Botsford/The Washington Post)

President Trump called Canadian Prime Minister Justin Trudeau to offer his condolences after a terrorist attack left six people dead at a mosque in Quebec on Sunday night, the White House and the Canadian government said Monday.

The call is Trump’s first to a foreign leader after a terrorist attack since he was sworn in as president on Jan. 20.

“President Trump expressed his condolences to the Prime Minister and people of Canada following the tragic shooting at the Centre culturel islamique de Québec, located in Québec City, and offered to  provide any assistance as needed,” Trudeau’s office said in a brief statement.

During his Monday afternoon press briefing, White House press secretary Sean Spicer said: “This is another senseless act of violence which cannot be tolerated. We condemn this attack in the strongest possible terms. It is a terrible reminder of why we must remain vigilant and why the president is taking steps to be proactive rather than reactive.”

Spicer said that Trump offered Trudeau U.S. support as Canadian authorities investigate the attack.

The mosque attack in Canada comes in the midst of a politically charged debate over Trump's order for a temporary ban on immigration from seven predominantly Muslim countries and a temporary suspension of the U.S. refugee program. The move has caused chaos and uncertainty in airports across the country. Opponents have responded with mass protests in major cities, including outside of Trump’s hotel in Washington, D.C.

Trudeau has said that Canada would welcome refugees turned away by the United States.

The motive for the deadly attack on the Quebec City mosque, which also left 19 people wounded, is still unknown.

Trump has not spoken publicly about the incident. In brief encounters with the press Monday morning ahead of his meeting with small-business owners at the White House, Trump made no mention of the attack as he criticized congressional Democrats for their opposition to his immigration order.

He also sent a series of tweets on Monday morning defending his “ban” and denouncing Senate Democratic leader Charles E. Schumer (D-N.Y.).