Mass graves of 1,700 Iraqi soldiers found in Tikrit

Iraqi forensic teams have begun to exhume suspected mass graves containing up to 1,700 Iraqi soldiers captured and killed by the Islamic State group (IS).

The 12 sites were found in the city of Tikrit, near the former US Army base, Camp Speicher, shortly after the city was recaptured from IS by the Iraqi army and Shia militias following a month-long seige.

The killing in June 2014 of mainly Shia soldiers from Camp Speicher became a notorious symbol of IS brutality, after the group posted videos and photographs of the execution by machine gun on social media.

The burial sites are partly in the presidential compound of former Iraqi president Saddam Hussein, which became IS' headquarters when they captured the city in 2014.

The militants questioned their victims to find out whether they were Shia before killing them, survivors have said.

DNA testing will be used to identify the bodies, with families of those killed pressuring the Iraqi government to identify the bodies.

"We dug up the first mass grave site today. Until now we found at least 20 bodies. Initial indications show indisputably that they were from the Speicher victims," Khalid al-Atbi told Reuters on Sunday.

"It was a heartbreaking scene. We couldn't prevent ourselves from breaking down in tears. What savage barbarian could kill 1,700 persons in cold blood?" he said.

Shia militia fighters have vowed to avenge the killings, and last year succeeded in steming IS' advance. However, they have also been accused of war crimes.

Around 30,000 fighters were involved in the offensive to take back Tikrit, launched on 2 March, two-thirds of them from Hasid Shaabi, or the Popular Mobilisation, which consists of several Shia militia supported by Iran.

The Iraqi army is now expected to turn its attention to the city of Mosul. This is IS's most important stronghold in Iraq, and will be more of a challenge than Tikrit for the Iraqi army and US-led air coalition.