"A mass grave has been found in Paktika. We have sent a delegation to investigate," Interior Ministry spokesman Yousuf Stanizai said in Kabul on Thursday, without giving details.
Another official in the same ministry said the grave was believed to contain the bodies of soldiers who were killed after surrendering to mujahidin fighters who toppled the communist government of president Najibullah.
"According to my information, there are some 530 bodies in the grave," he said, speaking on condition of anonymity.
"We believe that they were the defeated soldiers of Najibullah," he said.
First communist grave
If proven true, it would be the first mass grave found in Afghanistan containing communist soldiers.
Other graves have been found with the bodies of thousands of anti-communist mujahidin holy warriors.
"We believe that they were the defeated soldiers of Najibullah"
Interior Ministry spokesman
In 2002, months after US forces and several Afghan militia groups toppled the Taliban rulers, the bodies of thousands of Taliban fighters were found in a grave in northern Afghanistan.
Human-rights groups blamed the killing on Abdul Rashid Dostam, one of Afghanistan's most feared regional commanders, who is now the army chief of staff in President Hamid Karzai's government.
Similar mass graves have been found in the minority Hazara-dominated central province of Bamiyan.
Taliban forces were blamed for those killings.