Kabul  - Three Canadian soldiers were killed in a roadside blast in southern province of Kandahar, while another bombing in the same province killed three Afghan policemen and wounded 12 people, officials said Sunday.

The soldiers of NATO-led International Security Assistance Force were patrolling Saturday morning when the blast occurred, the Canadian defence ministry said in statement posted at its website.

Another Canadian soldier was wounded in the attack in Arghandab district, 14 kilometres west of Kandahar city in Kandahar province, it said.

Taliban spokesman Qari Mohammad Yousif Ahmadi, speaking from an undisclosed location, took responsibility for the attack and claimed seven Canadian soldiers and four Afghan forces were killed.

A bomb hidden in a pushcart exploded in Kandahar city on Sunday morning, killing three policemen and wounding five others and seven civilians, the provincial police chief said.

The cart was left in front of the Mirwais hospital in the western part of the city and detonated by remote control as a police vehicle was passing by, he said.

Ahmadi said Taliban fighters were behind the attack that he claimed killed five policemen.

Taliban militants steadily gained power in the past two years after their ouster in late 2001 in US military invasion. The militants stepped up their attacks on Afghan and international forces, with mainly using roadside and suicide bombings.

On Friday the militants killed four British troops in southern Helmand province. Three of the Royal Marines were killed by a suicide bomber believed to be 13 years old.

The use of child in the attack sparked widespread condemnation by several national and international officials including President Hamid Karzai and British Prime Minister Gordon Brown.

"Such unscrupulous use of children can not be justified under any circumstances. Forcing or coercing children directly into such action is wholly unacceptable by anyone's standards," the top UN envoy in Afghanistan, Kai Eide, said in a statement on Sunday.

"The killing of three Marines by a 13-year-old boy again demonstrates the Taliban's total disrespect for human right," Eide said. (dpa)