Canada has 2,800 troops in Afghanistan, but the mission has become increasingly unpopular at home and it is scheduled to be withdrawn at the end of 2011.
'CIA agents killed'
The deaths came just hours after news emerged that eight Americans were killed by a suicide attack at the US military forward operating base, Chapman, in southeastern Khost province, near the border with Pakistan.
The Washington Post newspaper, citing US officials, said the eight killed were working for the Central Intelligence Agency (CIA).
Defence officials said some people were wounded in the explosion but no US or Nato troops were among them.
Officials told the paper that a bomber managed to slip past security before detonating an explosive belt in a room used as a fitness centre.
The base is engaged in reconstruction projects, a key part of the strategy to stabilise the country by Barack Obama, the US president.
Washington has committed to send hundreds of US civilians to support work on development projects that aim to undermine support for the Taliban and other fighters.
And, according to the Washington Post, the CIA has been bolstering its ranks in Afghanistan in recent weeks, mirroring the increase in troops.
Wednesday's attacks are the latest in a wave that has sent military and civilian death tolls to the highest levels since the Taliban was ousted from power by US-led forces in late 2001.
Many civilians working outside Kabul have retreated to heavily fortified army bases as the security situation has deteriorated.
But foreign aid agencies warned earlier this year that the shift to the military bases, and the use of military personnel to carry out development projects, risked a dangerous blurring of the boundaries between troops and civilians.
Afghan civilian deaths
Intensified activity by US-led forces has also bred resentment among Afghans, particularly as local civilians have been killed in several attacks.
In the latest such case, Afghans took to the streets in different cities on Wednesday to protest against the alleged killing of 10 civilians, including schoolchildren, in military operations by international forces in the country's east.
A statement from the office of Hamid Karzai, the president, said the deaths occurred on Sunday in a remote part of Kunar province on the border with Pakistan.
In Jalalabad, capital of Nangarhar province, which borders Kunar, around 200 university students rallied in the streets on Wednesday, demanding those responsible for the alleged weekend attack be brought to justice.
In Kabul, the Afghan capital, a crowd of around 100 mostly young men gathered in a western district to vent their frustration at the killings.
"Obama! Obama! Take your soldiers out of Afghanistan!" the protesters chanted, wearing blue headbands with the words: "Stop killing us!"
Others held placards with pictures of young children they said were killed by foreign troops.
International forces in Afghanistan have strenuously denied the Karzai government's accusations.
Although UN figures show far more civilians are killed by the Taliban, deaths at the hands of foreigners spark wide resentment and in the country and undermine international forces' attempts to weaken the Taliban by building trust among the population.