The Taliban are in full control of 14 districts of the crisis-torn state and have "an active and open physical" presence in a further 263, the results of the study published on Tuesday showed.
About 15 million of the Afghan citizens live in the areas either controlled by the radical movement or in the districts that are often targeted by Taliban's attacks, according to the broadcaster's research.
The BBC investigation has revealed that the number of districts with Taliban's presence has increased since the mission carried out by the United States and its allies in Afghanistan ended in 2014 and the foreign troops were formally withdrawn from the country.
The research was conducted on August 23 — November 21, 2017, when the BBC reporters spoke to more than 1,200 individuals in every district of Afghanistan.
Over the years, Afghanistan has been facing an unstable political and humanitarian situation, which had worsened due to the activities of terrorist groups such as Taliban and Daesh.
In August 2017, Trump issued a new strategy concerning Afghanistan, which presupposed increase in US military presence in the country in order to force the Taliban group to negotiate a political settlement. Such move was believed to result in the end of the US longest foreign war. However, on Monday, Trump rejected the idea of negotiations with the Taliban in the wake of deadly terrorist attacks in Kabul, which claimed lives of hundreds of people.
The Taliban group operating in Afghanistan was accused by the US of providing a sanctuary to al-Qaeda and its leader Osama Bin Laden, who were blamed for the 9/11 attacks. The subsequent US-led coalition's invasion in Afghanistan led to the Taliban being driven from power in the country.