Prime Minister David Cameron says he wants to "further strengthen" relations between Britain and Afghanistan as he held discussions with President Hamid Karzai at Chequers.
President Karzai was the first international leader to visit Mr Cameron since he became Prime Minister on Tuesday.
The visit came a day after Afghanistan topped the agenda for talks between Foreign Secretary William Hague and US Secretary of State Hillary Clinton in Washington.
Mr Karzai is stopping in the UK on the way back from a week of talks with the Obama administration in the US, ahead of a peace gathering - or "jirga" - to be held in his country at the end of this month and the Kabul Conference on July 20.
A Downing Street spokesman said: "The Prime Minister was delighted to invite President Karzai to Chequers, the first formal visit by an international leader since the election.
"They discussed President Karzai's very successful visit to Washington, and the prospects for the peace jirga in Afghanistan at the end of May. Both the President and Prime Minister agreed that the relationship between Afghanistan and Britain should be further strengthened.
"The President and the Prime Minister expressed their admiration for the courage and skill of the British military in Afghanistan, and the sacrifices that British forces have made."
Mr Cameron will today hold further discussions at Chequers with Defence Secretary Liam Fox, national security adviser Sir Peter Ricketts and service chiefs.
Mr Hague said that the new Prime Minister had made Afghanistan "our top priority in foreign affairs" and would work with the US and international community to support Nato's strategy.
Mr Hague told BBC Radio 4's Today programme: "This is a crucial year, this may be a decisive year in Afghanistan. It is vital that we continue to make the military progress, the security progress, on the ground."
