SEOUL, South Korea - Prime Minister Stephen Harper laid a wreath at a Korean War Memorial on Thursday in honour of the Canadian soldiers who fought in the Korean war of 1950-53.

In Seoul for the G20 summit, Harper attended a moving Remembrance Day ceremony before the day's meetings commenced, accompanied by British Prime Minister David Cameron and Australian Prime Minister Julia Gillard.

Almost 27,000 Canadian troops participated in the war, fighting alongside South Koreans, Americans and other allies to push back communist forces in the North.

More than 500 Canadians lost their lives in the conflict, and about 1,200 were wounded or injured.

Another 7,000 Canadian troops stayed behind after the war to maintain a ceasefire.

Harper also honoured the Canadian troops who have served in hotspots around the world today.

"Today I also want to pay tribute to our brave men and women in uniform who continue the proud tradition of defending peace and freedom around the globe in places such as Afghanistan and Haiti," the prime minister said.

South and North Korea are still living with the legacy of the war that started 60 years ago. The border is heavily armed, and summit organizers have taken every precaution this week to make sure North Korea doesn't attempt to send a signal to powerful world leaders gathered in Seoul.

Canada's participation in the Korean war was controversial from the get-go.

Suspicious of the Americans' exuberance in fighting communist forces, then-foreign affairs minister Lester Pearson emphasized that Canadian troops were volunteering for the war effort to help the United Nations.

"Today we honour and remember those members of the Canadian Forces who fought in one of the toughest wars in our history, to defend South Korea against an oppressive communist invader," Harper said.

"Our forces fought bravely alongside our Allies to defend South Korea and played a pivotal part in ending the hostilities."