The national-security adviser to Afghan President Ashraf Ghani has resigned from his position, an Afghan official said on August 25.
A spokesman for the Afghan National Security Council confirmed to RFE/RL's Radio Free Afghanistan that Mohammad Hanif Atmar had resigned his post but did not give further details.
A statement from Ghani's office on August 25 said that Atmar has been replaced by Hamdullah Mohib, the Afghan Ambassador to the United States.
Atmar had previously served as the country's interior minister under former Afghan President Hamid Karzai. He has served as a close aide to Ghani since 2014.
Tolo News on August 25 published a copy of what it said was Atmar's resignation letter, reporting that he resigned due to "serious differences over policies and approaches at the top level of government."
The authenticity of the letter could not immediately be confirmed.
Atmar's resignation comes amid a deteriorating security situation in Afghanistan, which in recent weeks has been hit by several deadly attacks carried out by suspected Islamic State militants, including a rocket attack near the presidential palace in Kabul.