A suicide bomber has killed a Canadian soldier in the Afghan capital Kabul.
The bomber attacked the troops while they were on patrol
One Afghan civilian died as well as the bomber while three other Canadian peacekeepers were among 10 wounded in the attack outside their base.
A spokesman for the ousted Taleban regime claimed responsibility for the attack in a message to the BBC.
In December remnants of the Taleban warned that suicide bombers had infiltrated Kabul to carry out attacks on the US-backed authorities.
Officials say the explosion took place at 0825 (0355 GMT) as the troops were leaving their base in the west of the city for a patrol.
The International Security Assistance Force (Isaf) named the dead soldier as Jamie Brendan Murphy of Conception Harbour, Newfoundland.
The head of Nato, which has commanded Isaf since last August, condemned the attack as "shameful".
"But it will not detract from our commitment to help Afghanistan build a better,
more hopeful future," Jaap de Hoop Scheffer added.
The three injured soldiers were taken to the Isaf hospital where their condition was said to be stable.
Canadian and Afghan soldiers sealed off the area.
A French national in a nearby car suffered shrapnel injuries, a Western diplomatic source said.
The soldiers were in the last of three vehicles in a convoy when they came under attack.
"There was a bump in the road, and when they slowed down to pass over it a terrorist jumped on one of the vehicles and blew himself up," police official Ali Jan Askaryar was quoted as saying by the Associated Press.
Canadian peacekeepers console themselves after treating injured
A second bystander, Ahmad Skekib, recalled "a big explosion, then flames and smoke".
The BBC's Andrew North, who was at the scene of the attack, saw two damaged jeeps and a white sheet covering the remains of what was thought to be the bomber.
The Camp Julien base for the Canadian peacekeepers is a short distance away from the scene.
Hamid Aga, a spokesman for the Taleban, told the BBC that there would be more attacks on "foreign infidels".
Our correspondent reports that such claims have to be treated with caution, but this followed a Taleban warning last week of an impending wave of attacks.
In October, two Canadian soldiers died in a landmine explosion in Kabul and four others died earlier last year when they were bombed by mistake by a US fighter jet near Kandahar.
In the worst attack on international peacekeepers, four German soldiers were killed in a suicide attack on their bus last June.
Nato took control of Isaf in August 2002 and is considering expanding it to areas outside the capital.
Canadian soldiers make up the largest contingent of the peacekeeping force, having sent nearly 2,000 troops last August.