Shiite militiamen have discovered the mass graves of Iraqi soldiers allegedly massacred by the Islamic State of Iraq and Syria.

After the Islamic State overran government forces in Tikrit in June, the New York Times reported that the militants could have massacred a thousand Shiite Iraqi government soldiers that were based in Camp Speicher. The New York Times was unable to verify ISIS' claims of massacring the soldiers.

After government forces and Shiite militia slowly cemented their hold on the contested city of Tikrit, the New York Times reported on Wednesday that Shiite militiamen uncovered two graves in and around the village of Albu Ajeel, south of the city.  Tikrit is the birth place of the late dictator Sadam Hussein and a hub of Sunni Islam in Iraq.

Naeem al-Aboudi, spokesperson of the militia group Asaib Ahl al-Haq, told the Times in a phone interview that the graves contained about 300 to 400 bodies believed to be the Shiite soldiers captured when the ISIS overran Camp Speicher. He revealed that Sunni residents of the village had provided his militia with information about the location of the mass graves.

Al-Aboudi also told the New York Times that pictures of the bodies have been sent to the central morgue in Baghdad. He added that they were waiting for Iraqi health officials to come and remove the bodies from the graves.

The militia leader revealed that the Sunni residents told his men that some of the Albu Ajeel villagers had assisted the militant fighters in killing the soldiers, but some also helped survivors escape from the village.

Al-Aboudi said there was "unity" between the Shiite militiamen and the Sunni villages in the face of the common ISIS threat.

"This battle today has proven to the world that the Sunnis and Shia are united," he noted.