UK forces in Afghanistan will be reinforced if commanders on the ground request it, Britain's most senior military officer has said.
Sir Jock said the Afghan mission always appeared difficult
The Chief of Defence Staff was speaking a day after three soldiers died in an ambush by Taleban militants.
Air Chief Marshal Sir Jock Stirrup said it had been accepted operations in the country would result in casualties.
He also told the BBC control of the Iraqi city of Basra could be handed to local security forces early in 2007.
A British soldier was killed in a mortar attack on a base in the southern city on Tuesday.
But patrols have recently been doubled under a new security plan agreed between UK and Iraqi ministers in an attempt to curb militias and tackle corruption.
"We are now on a good path to hand over provincial control of Basra some time in the first part of next year," Sir Jock told BBC Radio 4's Today programme.
"But these are difficult issues we are grappling with and I can't forecast what will happen over the next several months.
"This is a dynamic situation and we have to be able to react to any changes that occur. At the moment we are making good progress."
Nearly 4,000 UK troops are currently deployed in Afghanistan, the majority in Helmand as part of the Nato-led International Security Assistance Force (ISAF).
The attack on Tuesday brings to nine the number of British troops who have been killed in action in the country this year.
Sir Jock said the UK would "continue to put into Helmand whatever our commanders on the ground feel they need to deliver the mission effectively within the bounds of sensible military risk".
He said: "It is turning out pretty much the way we foresaw.
"I know some people claim that we said this was going to be easy - I certainly never said that and I certainly never believed it.
"We knew it was going to be difficult, we knew we were going to take casualties, so there's been no surprise at that."
He added: "Of course, our thoughts are very much with the families and loved ones of those who died."