OTTAWA -- Canadians across the country are mourning those killed in Friday’s shooting in Fredericton, Prime Minister Justin Trudeau said Friday.

"Canadians across the country were shocked to wake up to news of the shooting in Fredericton that left four people dead, including two police officers," Trudeau said in a statement.

"There is no greater gesture than to put oneself in harm's way to protect the life of another. This morning, first responders rushed to the scene of danger. They did not think twice about what they had to do to keep their fellow Canadians safe. They were unflinching in their duty. We will not forget the two fallen police officers whose sacrifice no doubt saved lives and prevented even greater tragedy."

Trudeau said he's spoken with Fredericton Police Chief Leanne Fitch, Mayor Mike O’Brien, and New Brunswick Premier Brian Gallant.

"The people of Fredericton are courageous, strong, and resilient. Canadians stand with you during this difficult time," he said.

Trudeau again addressed the tragedy while speaking to a community still recovering from its own mass shooting: Toronto’s Danforth neighbourhood.

“As we remember the terrible tragedy that struck two weeks ago, the loss of life, the way the community came together, there is a great town a few hours east of here, our friends in Fredericton, who are going through a very, very difficult night,” Trudeau said.

“And if we could all send them our best love and our best support for our fallen officers who are there protecting us and the people who died in a terrible tragedy.”

In a statement, Liberal MP for Fredericton Matt DeCourcey called it an “unspeakable tragedy.”

DeCourcey offered his support to the Fredericton Police Force.

“They have the unthinkable task of keeping our community safe while grieving the loss of colleagues and friends in the days and months ahead. This will be no easy task,” he said.

He said his community is “unaccustomed to such violence.”

“We will do what is required to support each other and we will grow stronger together,” he said.

Public Safety Minister Ralph Goodale told reporters in Sarnia, Ont., that the Fredericton shooting is a huge tragedy.

Goodale provided no details about the alleged shooter, who is in police custody and being treated for serious injuries, according to Fredericton police. He deferred to local police and said it's very early, with many details unknown.

"What we do know is four Canadians are dead and that is a huge tragedy for the whole country, and all Canadians I'm sure would want to extend their condolences and their sympathies to all the families," he said.

In an earlier tweet Goodale said he was "deeply concerned" about the shooting, and that RCMP is assisting.

"All of Canada stands with the two brave Fredericton Police officers who lost their lives protecting their community today. Their families, friends and loved ones have our deepest condolences," he added.

'A tragic morning'

In an interview with CTV News Channel, Premier Gallant offered his condolences to the victims and their families, as well as to the Fredericton police force.

"You wake up one day, think it’s going to be just a typical day, and then all of a sudden you’re going to get this news. What a terrible, horrendous situation to be in. I can’t even fathom what the families of the victims are going through," he said in an afternoon interview with CTV News Channel.

Earlier in the day he told CTV that that the shooting puts things in perspective, calling it a “tragic morning” in his province.

"When we see this type of tragic event, what our first responders do for us Canadians -- they put themselves in harm's way and they do so to keep us all safe.”

Gallant said he was working in his Shediac Bay-Dieppe riding office Friday morning when his chief of staff called to let him know what happened, and made his way to Fredericton after that.

"It is still a shock," he said.

"I can tell you my wife and I were completely shocked and deeply saddened by the tragic events. Obviously, like anybody else, when you hear something like this you automatically think of the family and the people that would be close to those that we lost and you think about your own perspective."

Gallant says his wife's father was an RCMP officer.

"This type of thing certainly hits home for my wife and her family," he said. “The City of Fredericton, the province, will get through this."

Condolences streaming in

Conservative Leader Andrew Scheer also tweeted his reaction.

"Shocking and devastating news out of Fredericton this morning. Jill and I are praying for the families of these brave officers and everyone impacted by this morning’s violence. #FrederictonStrong," he said.

NDP Leader Jagmeet Singh called the news "very tragic."

"My heart is with all those impacted by the shooting, along with all first responders at this time," he wrote on Twitter.

Federal Health Minister Ginette Petitpas Taylor, who represents New Brunswick's Moncton-Riverview-Dieppe riding, thanked first responders.

"Heartbroken to hear of today’s tragic shooting in Fredericton; my thoughts are with the victims and their loved ones. New Brunswickers are one family, and we grieve together," she wrote on Twitter.