(CNN) -- Afghan President Hamid Karzai dismissed the country's national intelligence chief on Wednesday -- a move that coincides with other Cabinet-level shakeups as Karzai's government struggles to confront security challenges posed by Taliban fighters and an impending NATO withdrawal.
Rahtamullah Nabil, 42, whose two-year term has expired, is to step down from his post atop the National Directorate of Security, said a presidential spokesman who declined to be named.
He is expected to hand over the position to Karzai loyalist Asadullah Khalid.
The Pashtun leader is the nation's current minister of tribal and border affairs, but has come under scrutiny for alleged human rights abuses.
"This is a government with a checkered past that has come under serious accusations of torture," said Heather Barr, a Kabul-based spokeswoman for Human Rights Watch. "So the leadership of this institution really needs to be someone who is above suspicion."
The NDS is Afghanistan's main intelligence agency that reports directly to the president and National Assembly.
But perhaps more indicative of an Afghan government at odds is Karzai's choice for replacements at the Ministries of Defense and Interior, which have been vacant for weeks.
The Afghan president tapped Bismillah Khan Mohammedi -- a politically connected former Interior Minister -- to head up the Defense Ministry.
The move is expected to stir discord among parliament lawmakers who recently dismissed the Tajik leader from his post at the Interior Ministry, citing corruption and his lack of ability to stem cross-border attacks from Pakistani-based militants.
Ghulam Mujtaba Patang, a senior Afghan security official, is to head up the Interior Ministry, the spokesman said.
The cabinet shakeup comes ahead of the country's 2014 presidential elections, which also coincides with the drawdown date for NATO forces.
CNN's Ab Qadir Sediqi in Kabul contributed to this report