A blast hit a U.S. military convoy in Kabul on Sunday (September 17) wounding three soldiers and killing a passer-by, a day after U.S.-led forces launched a new offensive against a resurgent Taliban. Police said the blast was caused by a suicide bomber. A U.S. spokesman said it was a roadside bomb. A suicide bomber attacked a Canadian military convoy in southern Afghanistan on Sunday (September 17), killing himself and a passer-by. A passer-by was killed and five were wounded when the suicide bomber rammed his mini-van into the Canadian convoy on the outskirts of the southern city of Kandahar, said police officer Mohammad Yaseen. A spokesman for the NATO-led force said three of its soldiers were very slightly hurt and one vehicle slightly damaged. The Taliban and their militant allies have unleashed a wave of attacks, including scores of suicide blasts, on government and foreign troops this year. Security forces have responded with a series of offensives. NATO commands about 20,000 troops in Afghanistan, in the north, west and south. The United States has a similar number in a separate force, operating in central and eastern provinces. About 130 foreign troops have been killed in Afghanistan this year, most of them Americans, British and Canadians. NATO and Afghan government forces have forced Taliban troops out of a southern Afghan district after a two-week operation in which NATO said hundreds of militants were killed. The offensive, codenamed Operation Medusa, was launched on Sept. 2 to clear well dug-in Taliban forces from a farming district about 25 km (15 miles) west of the southern city of Kandahar. NATO said more than 400 insurgents had been killed in Operation Medusa, the alliance's biggest ground offensive against an increasingly active Taliban. The British commander of NATO troops in Afghanistan, Lieutenant General David Richards, said on Sunday "This is not an occasion to rest on our laurels. Having created a secure environment of the area it is now time for the real work to start. Without security there can be no reconstruction and development and without reconstruction and development as we all know there can be no lasting security." "The Taliban sent out in this battle to challenge us and more importantly the government of Afghanistan to take them on. We could not duck this challenge and hope to succeed here and we had to prove to the people of the region and indeed the country that NATO ISAF can and will win operating in close conjunction with our afghan allies," said Richards. NATO commands about 20,000 troops in Afghanistan, in the north, west and south. The United States has a similar number in a separate coalition force, operating in central and eastern provinces.