An Afghan investigation has found that weak leadership, misuse of resources and lack of coordination between services are the main reasons a strategic northern city briefly fell to the Taliban.

Amrullah Saleh, head of the investigating team and a former intelligence agency chief, said Saturday that without U.S. air support, government forces would have been unable to take back the city.

Kunduz city, capital of the province of the same name, was overrun by Taliban gunmen on Sept. 28. The insurgents held the city for three days before a government counter-offensive was launched.

Troops took more than two weeks to bring the city back under government control.

Saleh's investigation into Kunduz is the first to release results to the public, in the form of a 30-page summary.