More than 30 members of Parliament are calling on Canada to support an immediate ceasefire in the conflict between Israel and Hamas that has left thousands dead in two weeks.

In a letter addressed to Prime Minister Justin Trudeau on Friday, 33 MPs – 23 of whom are Liberals – say they "have a duty to be the voice of our constituents in Ottawa. And they, like all of us, have been watching with worry and with horror the events unfolding in Israel and in Gaza."

The other signatories include members of the NDP and Green Party.

In their letter, the MPs "condemn the killing of innocent Israeli civilians … by the terrorist group Hamas," adding that, "Violence and acts of terror are never the way to lasting peace and justice. We call for the release of all hostages."

"Canada has long been a voice for peace. The longer this conflict goes on, the more innocent civilians will pay with their lives. We demand that Canada join the growing international call for an immediate ceasefire. Canada must act before more innocent children are killed," the letter says.

The MPs also call on Canada to help open a humanitarian corridor and to "strongly stand up for international law," namely to protect innocent civilians.

"Canada must recognize that, for generations, the Palestinian people have suffered under occupation. Canada must reaffirm its commitment to a free Palestinian state living peacefully alongside a free Israeli state and do all it can to bring the parties to the negotiating table."

Hamas, which rules Gaza, launched a surprise attack on Oct. 7, which to date has left more than 1,400 people dead in Israel, mostly civilians, The Associated Press reports. Around 200 people have also been taken hostage.

The Canadian government has designated Hamas as a terrorist entity for more than two decades.

Israel has responded to the attack with airstrikes, a siege that has cut off food, water and electricity to Gaza and ordered residents in the north to move south ahead of an expected ground offensive.

Israel and Egypt imposed a blockade on Gaza in 2007 after Hamas came to power.

The Associated Press says more than 4,100 people have been killed in Gaza, citing the Health Ministry run by Hamas. The figure includes a disputed number of people who died in a hospital explosion earlier this week, although some estimates are that hundreds were killed.

Appearing on CTV's Power Play on Friday, Liberal MP Salma Zahid, who chairs the Canada-Palestine Parliamentary Friendship Group, said it is important that Canada do whatever it can to protect civilians.

"As a mother, it is really very difficult for me to see those videos and pictures coming out seeing the loss of innocent kids," she said. "So the longer this conflict goes on, more innocent civilians will have paid with their lives."

Asked multiple times about Israel's right to defend itself, something Trudeau and other leaders have highlighted since the conflict began, Zahid said in part that "wars also have rules."

"Anything against the international law should not happen, like the lives of the civilians should be protected," she said. "It is really very important. What we are seeing is the innocent children are being killed."

Speaking to reporters in Brampton, Ont., Friday during a funding announcement on housing, Trudeau responded to a question on whether his caucus is divided over Canada's response to the war.

"Everyone is hurt and hurting, everyone is grieving, everyone is scared of what this means right now, in terms of whether you can send your kids to school safely or whether you're going to be harassed walking in the streets or shouted at on a university campus. And they're scared about what this might mean around the world, in the region and elsewhere," he said.

"People are worried, people are scared, and Canadians of all backgrounds who are represented in Parliament are reflecting the very real fears and concerns that everyone has."

Trudeau added that as parliamentarians their job is not only to speak for their constituents but also "reassure everyone that this is Canada, and here our differences must and will remain a source of strength."

With files from The Canadian Press and The Associated Press