The commander of Nato forces in Afghanistan has insisted that the tide was turning against the Taliban.
But US general David Petraeus warned that there was more "tough fighting" ahead in order to ensure progress was maintained.
The assessment came after an intense period of violence in the run-up to the country's second set of parliamentary elections next month.
On Sunday, the Ministry of Defence named the latest British casualty as 25-year-old Lance Corporal Jordan Bancroft, from the 1st Battalion The Duke of Lancaster's Regiment. He was killed during gun battle with insurgents in southern Nad-e Ali, Helmand province on Saturday.
Nato deaths so far this year have already topped 450 - compared with 520 in the whole of 2009.
However, in an interview with the BBC, Gen Petraeus indicated he believed the troop surge was working. "The momentum that the Taliban have established over the course of recent years has been reversed in many areas and will be reversed in the other areas as well. This will entail tough fighting," he said.
Meanwhile, four troops were killed by roadside bombs in Afghanistan.
The attacks came in the north, south and east of the war-torn country, Nato said.
One victim was American, the nationalities of the others were not released but sources said they were not believed to be British.
The deaths bring the number of foreign forces killed in Afghanistan this month to 46.
