Britain has 5,000 soldiers in Afghanistan, where fighting against the Taliban this year has been the fiercest since Kabul fell in 2002.
David Richards, a British general and the head of the Nato-led International Security Assistance Force, has said the British are facing their bloodiest fighting since the Korean war.
With a resurgence in support for the Taliban, the fighting in Afghanistan has become more intense and suicide attacks are being used more frequently.
Blair flew to Afghanistan from Pakistan, where he had held discussions with Pervez Musharraf, Pakistan's president. The leaders had discussed the Taliban, the pooling of their counter-intelligence resources and militancy in some of Pakistan's religious schools.
Fighting has grown fiercer with
the resurgence in support for the Taliban
Taliban and other fighters are known to be sheltering in the borderlands between Afghanistan and Pakistan.
Afghan intelligence officials have criticised the West for not putting greater pressure on Pakistan and say they continue to submit evidence of the Pakistani government's support for the Taliban.
Pakistan says it is doing everything it can to target the fighters in the borderlands.
Following a major redeployment to the Taliban's southern heartland, British casualty rates in Afghanistan are now much higher than its casualties in Iraq, with 36 British soldiers killed since June.