KABUL, Afghanistan — In the second major attack in two days, at least 37 people were killed yesterday when a suicide bomber rammed his vehicle into a Canadian military convoy in a market in southern Afghanistan, authorities said. The dead were all Afghan civilians, said Abdul Razeq, the border police chief in Spin Buldak, a town that lies close to Pakistan in Kandahar province. At least 30 other people were injured.

The bombing came a day after the most devastating attack this violence-torn country has seen since the overthrow of the Taliban government at the end of 2001. On Sunday, a suicide bomber blew himself up in a crowd of men and boys who had gathered for a dog-fighting match just outside Kandahar city. The number of dead in that attack has reached 100, Governor Asadullah Khalid of Kandahar said yesterday.

Mr. Khalid spoke at a memorial service for the likely target of the bombing, Abdul Hakim Jan, a former provincial police chief who made his name as an enemy of the Taliban during the Islamic movement’s rise to power in the 1990s. More recently, Mr. Jan headed an anti-Taliban militia outside Kandahar, and Mr. Khalid said he had warned Jan that he remained a Taliban target.

Yesterday’s bombing in Spin Buldak wounded two Canadian soldiers, part of the North Atlantic Treaty Organization force operating in Afghanistan. Kandahar province, the cradle of the Taliban movement, has seen heavy fighting in the past two years with the resurgence of the radical movement. A purported Taliban spokesman, Qari Yousef Ahmadi, said his group was behind the blast.

As elsewhere in Afghanistan, the Taliban fighters in Kandahar increasingly have opted for suicide attacks and roadside bombs, tactics commonly used by insurgents in Iraq. In 2007, the country recorded more than 140 suicide bombings, a record since the American-led invasion in 2001.

Whereas past assaults have focused on NATO troops and Afghan soldiers and police, in recent months militants have shown themselves more willing to strike at civilians, whether directly or indirectly, in attacks that sometimes have claimed dozens of lives. Three months ago, about 70 people died in Baghlan, in what until Sunday was the worst suicide bombing since 2001. Among the dead were scores of schoolchildren who had turned out to greet a delegation of dignitaries. In January, a team of militants mounted an attack on Kabul’s only five-star hotel, battling past security barriers and armed guards to penetrate the interior.