KABUL: The head of Afghanistan's main intelligence agency resigned on Thursday over disagreements with President Ashraf Ghani, laying bare divisions that have hindered efforts to fight the growing Taliban insurgency.

The resignation of Rahmatullah Nabil follows a series of setbacks in recent months including the fall of the northern city of Kunduz to the Taliban and an insurgent raid on Kandahar airport in the south on Tuesday in which 50 civilians, police and security personnel were killed.

Already without a permanent defence minister due to conflicts within Ghani's national unity government, the country now has no spy chief just as the Kandahar raid underlined the Taliban's ability to inflict serious damage on its forces.

Nabil, who strongly opposed Ghani's moves toward a rapprochement with Pakistan, said in his letter of resignation from the National Directorate of Security (NDS) that there had been “a lack of agreement on some policy matters” in recent months.

He said the president had imposed unacceptable conditions on the way he did his job, with “repeated verbal summons” that put him under impossible pressure and forced his resignation.

Relations between Ghani and the NDS had been strained since at least the fall of Kunduz, which caught security forces badly unprepared and which an inquiry last month blamed on poor leadership.

Later, Ghani dismissed some NDS officials, including the provincial chief of the agency, who he said had neglected their duty to defend Kunduz. The Taliban held the city for several days before government troops could regain control.