The new NATO chief has vowed to strengthen military efforts to counter an insurgency in Afghanistan but said peace talks with certain groups were an option to end mounting violence.

Anders Fogh Rasmussen, making his first visit to Afghanistan as head of the 28-nation alliance, told a news conference with Afghan President Hamid Karzai that he was ready for ‘pragmatic steps’ to improve security.

If this took ‘talks with a number of groups within the Afghan society, I'm ready to do that’, the new secretary general said.

‘I think it is a prerequisite that the Afghan government can conduct the talks and negotiations from a position of strength. There is no alternative whatsoever to continued and strengthened military efforts,’ he added.

Another condition should be that groups that join any talks ‘put down their weapons and abide by the laws in this country’.

Mr Rasmussen said he had chosen Afghanistan for his first official visit since taking office on Monday because the country was a priority for the NATO alliance.

His trip came as the Pentagon announced a strategy review by the commander of international forces in Afghanistan, US General Stanley McChrystal, had been delayed and would not include a formal request for more troops.

Afghan authorities announced troops were battling on multiple fronts to secure flashpoints before the 20 August vote election and unveiled stringent plans to ban traffic and mobilise troops to safeguard polling day.

Mr Rasmussen, who is due to meet General McChrystal in Afghanistan, said NATO's International Security Assistance Force would do its best to help protect the polls against attacks.

Yesterday a roadside bomb struck a truck carrying people in southern Afghanistan killing 21 civilians and wounding six, an Afghan general said today.

General Sher Mohammad Zazai, commander of an Afghan military unit in Helmand province, said the explosion took place in Garmsir.