CHICAGO: Afghan President Hamid Karzai arrived in Chicago on Friday ahead of talks with US President Barack Obama and other Nato leaders at a key summit for Afghanistan's future, an alliance official said.

Obama will hold one-on-one talks with Karzai on Sunday on the sidelines of the summit, at which Nato allies will chart the final two years of the war before 130,000 foreign combat troops are withdrawn in late 2014.

The summit will also seek consensus on the structure and financing of the estimated $4.1 billion annual cost of Afghan forces after 2014.

Obama last met Karzai during a surprise trip to Kabul earlier this month when the two leaders inked a deal cementing 10 years of US aid for Afghanistan after Nato combat troops leave in 2014.

The two-day summit, which will continue on Monday, will gather Nato's 28 member states as well as leaders from more than 30 nations and international organisations, including Pakistani President Asif Ali Zardari.