A minibus packed with civilians struck a roadside bomb in southern Afghanistan early today, killing six on board and wounding nine, officials said.
The blast hit the bus in the Maiwand district of Kandahar province, according to provincial spokesman Zalmai Ayubi.
A Nato patrol arrived soon after the explosion and treated the wounded at the scene, the coalition command said.
US and Nato forces are stepping up operations against the Taliban in Kandahar and nearby Helmand province. July was the deadliest month for US forces in the nearly nine year war, with 66 troops killed. Overall Nato deaths were highest in June, with 103 troops killed.
The escalation in military operations also threatens more civilian casualties, potentially undermining support for the US-led mission among Afghans as well as the public in troop-contributing nations.
In the Afghan capital, Kabul, more than 400 demonstrators marched toward the presidential palace to protest the alleged killing of 52 civilians by a Nato rocket strike in the south. Nato has disputed the number of deaths.
Afghan and Nato representatives are conducting a joint investigation to find out the truth about the attack in Helmand province's Sangin district, but the Afghans gathered in downtown Kabul said they were sure the international forces were to blame.
They carried photos of children allegedly killed or wounded in the strike and shouted "Death to America! Death to Nato!"
In a letter to Nato-led forces, the top US and coalition commander, Gen. David Petraeus, reminded his troops they cannot succeed in turning back the Taliban without "providing them security and earning their trust and confidence".
"The Taliban are not the only enemy of the people," Petraeus said in the letter, a copy of which was obtained by The Associated Press. "The people are also threatened by inadequate governance, corruption and the abuse of power - the Taliban's best recruiters."
Petraeus told his troops to "hunt the enemy aggressively" but "use only the firepower needed to win a fight".
"If we kill civilians or damage their property in the course of our operations, we will create more enemies than our operations eliminate," he said.
Also today, the last troops from the 1,600-member Dutch military contingent were leaving the country, marking an end to the Netherlands' four-year mission in the central province of Uruzgan. They will be replaced by American, Australian, Slovak and Singaporean forces.
The departure of the Dutch from Uruzgan marked the end of a mission that was deeply unpopular in the Netherlands, but widely seen in Afghanistan as among the most effective. Twenty-four Dutch soldiers were killed since the mission began in 2006.
Prime Minister Jan Peter Balkenende's government collapsed earlier this year over disagreement among coalition members on whether to keep troops in the country longer. His Christian Democrat party suffered heavy losses at parliamentary elections in June.
The Dutch pioneered a strategy they called "3D" in Afghanistan - defence, diplomacy and development - that involved fighting the Taliban while at the same time building close contacts with local tribal elders and setting up numerous development projects.
Dutch troops, some of them riding bicycles, mingled closely with the local population and often did not wear helmets while walking around towns and villages as a way of winning the trust of wary local tribes.
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