Prime Minister Stephen Harper called on Russia to stop blocking United Nations attempts to impose sanctions on the "murderous" Syrian regime of Bashar Assad.
But the prospect of that succeeding, or any other attempt to sway Russia, appeared doomed by deteriorating relations between Washington and the Kremlin over accusations that Moscow was supplying attack helicopters to its longtime ally in Damascus.
Harper singled out Russia by name during question period in the House of Commons on Wednesday, urging it to join in the international effort to impose binding sanctions on the Assad regime.
Canada has been attempting to persuade Russia to stop supporting its Middle East ally as part of a broader effort led by the Obama administration.
Russia, a permanent member of the UN Security Council, has opposed any use of force to remove Assad, or any resolutions on sanctions. Opposition groups say 13,000 people have been killed in the 15-month Syrian uprising.
"We encourage Russia and others to join with us to apply binding sanctions against what is a murderous regime," Harper said, calling the Syrian situation unacceptable to Canadians and the international community.
Harper also appeared to be referring to China, the other permanent member of the security council that has backed Syria.
Harper spoke in response to a question by NDP Leader Tom Mulcair, who asked the prime minister about diplomatic attempts to sway Russia.
"We have all witnessed the horrors in Syria with the Assad regime, where innocent children are now being targeted," Mulcair said.
"Canadians feel the pain of the Syrian people."
A UN report released earlier this week accused Syria government forces and their militias of abusing children as young as nine. It accused them of killing and maiming, arbitrary arrest, detention, torture, and sexual violence, and using children as human shields.
U.S. Secretary of State Hillary Clinton warned the Syrian conflict could escalate dramatically because Russia is sending attack helicopters to Syria for use by the Assad regime.
Russian Foreign Minister Sergey Lavrov denied the claim Wednesday. Clinton fired back, accusing Russia of risking "vital interests in the region and relationships" by blocking an international plan to take Assad out of power.
Foreign Affairs Minister John Baird was planning his own call to Lavrov, but as of Wednesday evening it had yet to happen. Baird has already met with Russia's ambassador to Canada to press the case for Assad to step down.
The fighting continued to intensify in Syria Wednesday as government forces reportedly took back a rebel-held area near the Mediterranean coast.
With the bloodshed ramping up, France joined the UN in declaring Syria was in a state of civil war. "When many groups belonging to the same people tear each other apart and kill each other, if you can't call it a civil war, then there are no words to describe it," French Foreign Minister Laurent Fabius told a news conference in Paris.
-- The Canadian / Associated Press