Nato has agreed to fund the Afghan security forces until the end of 2017.
Leaders from the 28 member states came to the decision at Celtic Manor in Newport, South Wales, during the first day of the Nato Summit.
The alliance also received a co-signed letter from the two Afghan presidential candidates currently locked in a legal wrangle, reaffirming their commitment to resolving the issues in order to allow the US to withdraw combat troops by the end of the year.
An audit of votes is ongoing, following a run-off ballot between Ashraf Ghani and Abdullah Abdullah, the opposing candidates. Afghanistan cannot co-sign the agreement with the US until it has a permanent president in place.
Nato plans to reform its mission in the new year, installing a non-combat force to train and support the Afghan forces. The country's security will be placed in the hands of the 350,000-strong Afghan security and police forces.
"Without a signature there can be no mission. Although our military commanders have shown great flexibility in their planning, time is short. The sooner the legal framework is in place the better," Nato Secretary General Anders Fogh Rasmussen told reporters.
"I can confirm we received a message from the two presidential candidates indicating that they will do all they can to reach a political agreement. If that materialises, we will warmly welcome it."
Nato is yet to confirm the exact nature of the role it will play in Afghanistan in the future. While it has reconfirmed financial support, a figure has yet to be finalised but officials said they are confident it will mirror the $4.1bn agreed at the Chicago Summit two years ago.
Nor has it been able to confirm the numbers of non-combat troops it will have on the ground. With the political deadlock in Afghanistan, many nations have been reluctant to commit forces.
The results of the audit are expected on 10 September but Afghan President Hamid Karzai has warned he may not be prepared to stay in his role until the date arrives. Afghanistan could then be faced with a presidential void.