The latest deaths take the number of British troops who have died in Afghanistan since operations began in October 2001 to 195.
The latest deaths come after new Nato Secretary General Anders Fogh Rasmussen, who is in Afghanistan, said more troops were needed in the country.
He told BBC Radio 4's Today programme: "I have seen progress in the south, not least thanks to the increase in the number of troops. So definitely the number of troops matters.
"However, we also have to realise that there is no military solution solely.
"We have to provide the Afghan people with better life opportunities as well if we are to win hearts and minds, and this will be at the core of our new strategy."Source: BBC, Friday, 7 August 2009 14:51, Guardian, Saturday 8 August 2009 11.55 BST