The British Prime Minister has become the first Western leader to visit Afghanistan since the Taliban was toppled.
Mr Tony Blair flew into Bagram airbase near Kabul, accompanied by his wife Cherie, on a surprise visit which has been shrouded in secrecy.
Mr Blair will meet Major General John McColl, the British commanding officer of the International Security Assistance Force (ISAF), deployed to aid Afghanistan's interim administration.
The Prime Minister, who flew into the base on the flight deck of an RAF Hercules transport plane from the Pakistan capital Islamabad, is also going to meet some of the 500 British troops - mainly from the Royal Marines and the 2nd Battalion Parachute Regiment - who are based in Afghanistan.
He is expected to thank them for their work so far and then host a news conference where he is expected to stress the international community's long-term commitment to the country.
Mr Blair and his wife Cherie were wearing long coats against the freezing temperatures as they stepped off their blacked out aircraft to be met by acting head of state Mr Hamid Karzai and his wife.
Before meeting British troops, the two planned a session of private talks and Mr Blair is also due to meet United Nations special envoy Mr Lakhdar Brahimi.
PA