Hamid Karzai spoke as the 2,500-member national consultative council of Afghan elders known as the Loya Jirga started in Kabul on Thursday.
The four-day meeting will discuss the bilateral security pact that defines the role of thousands of U.S. troops who will remain after the NATO combat mission ends in 2014.
Karzai told the gathering that President Barack Obama assured him actions by U.S. forces after 2014 will respect the safety and security of Afghans.
The elders have the right to revise or reject any clause of the deal. Their decision will have significant influence on parliament, which has to endorse the pact.