Security officials have confirmed that two explosions were reported in Gardez city in Paktia on Tuesday morning.
A police source said the explosions occurred close to the police headquarters and that clashes are underway.
According to the Ministry of Interior, insurgents targeted the police training academy close to the police headquarters.
Insurgents detonated a car bomb and then entered the training center. Clashes between security forces and insurgents are ongoing, the MoI said.
TOLOnews journalist at the scene says there are many ambulances at the scene.
Meanwhile, another source said the first vehicle used in the explosion had been a Humvee.
No further details were provided nor were details regarding casualties provided, however there are fears that a number of people were wounded.
The Taliban has claimed responsibility for the attack and confirmed one of the vehicles used in the attack was a Humvee.