Crowds of protesters held rallies across Canada Saturday to denounce the blockade against Gaza and to demand that Ottawa press Israel to deal with human rights issues in the Hamas-ruled territory.

In downtown Montreal, protesters marched through the streets repeating "Boycott Israel" and "Free Palestine."

Organizers said they are angry at the manner in which Israel handled a flotilla of ships that tried to bring aid supplies to Gaza last weekend. Nine activists were killed after Israeli commandos boarded the largest ship in the flotilla.

Prime Minister Stephen Harper issued a statement following the raid. It said that Canada "regrets" the deaths and that Ottawa was seeking more details "to shed light on what exactly happened."

But protesters called on the Harper government to take action on the matter.

"It is unfortunate the Canadian government does not stand up for international law," said Laith Marouf, one of the organizers of the Montreal protest.

About 800 pro-Palestinian demonstrators also rallied outside the Israeli consulate in Toronto before marching to the downtown core, accompanied by a police escort.

"I think it's despicable. You have a group of human rights activists or humanitarians who basically just want to go and provide aid," said 29-year-old Ehssan Tehrani. "I don't think anyone should be denied access to these basic necessities of life."

In Edmonton, activists called for a boycott of goods produced in the Middle Eastern country.

"Israel has really sort of ignored the international community so we think it's time to put direct pressure on Israel," said Scott Harris, with the Palestine Solidarity Network.

His group is campaigning for Mountain Equipment Co-op to end its partnerships with Israeli factories, and is asking MEC's customers to boycott 31 Israeli-made products it carries.

Similar demonstrations were organized from Vancouver to Halifax, as well as in dozens of cities around the world.

They took place against the backdrop of a peaceful raid by the Israeli navy of another ship that tried to reach Gaza early Saturday. Israeli police said the 19 people on board would be deported within hours.

"The question goes beyond the situation that we faced throughout the week," said Henry Habib, a political science professor at Concordia University. "It goes to the blockade."

Israel has placed tight restrictions on goods entering Gaza since the Islamic militant group Hamas seized power in a violent battle there in 2007.

Hamas, which is considered a terrorist group by several Western countries, won legislative elections in Gaza a year earlier.

"Israel looks at its security and that's the reason they set up that blockade," Habib told CTV News Channel. "On the other hand, you have the question of the Palestinians, a humanitarian question, a question where people are suffering."

"We're going to hear a lot about people objecting and people protesting, which is fine," he added. "But we should come to the basic question: you have to resolve the Israel-Palestine issue."

With a report from CTV Edmonton's Sonia Sunger and files from The Canadian Press