A former child soldier who was the youngest ever Guantanamo Bay detainee will receive an apology and millions of dollars in compensation by the Canadian government, according to reports.

Omar Khadr, who pleaded guilty to killing a US soldier in Afghanistan when he was aged just 15, is set to receive a settlement of more than CA$10.5m (£6.3m, €7.2m) in a deal negotiated between the government and Khadr's lawyers last month, according to The Associated Press.

It comes after Canada's Supreme Court ruled he'd been interrogated under "oppressive circumstances".

Canadian-born Khadr was 15 when he was captured by US troops following a firefight at a suspected al-Qaida compound in Afghanistan in 2002.

The teenager was suspected of throwing a grenade that killed US Army special forces medic Sgt. First Class Christopher Speer.

Khadr was captured and taken to Guantanamo, where he was ultimately charged with war crimes by a military commission.

He pleaded guilty in 2010 to charges including murder and was sentenced to eight years plus the time he had already spent in custody.

He returned to Canada two years later to serve the remainder of his sentence and was released in May 2015 pending an appeal of his guilty plea, which he said was made under duress.

In total, Khadr spent 10 years in Guantanamo Bay's military prison, located on the island of Cuba; his case received international attention after some dubbed him a 'child soldier'.

He was the youngest and last Western detainee held at the military prison.

Khadr's lawyers have long said he was pushed into war by his father, Ahmed Said Khadr, whose family stayed with Osama bin Laden briefly when Omar was a boy.

Young Omar
A young Omar Khadr Wikipedia/Khadr family

Omar's Egyptian-born father was killed in 2003 when a Pakistani military helicopter shelled the house where he was staying with senior al-Qaida operatives.

After his 2015 release from prison in Alberta, Omar apologised to the families of the victims. He said he rejects violent jihad and wants a fresh start to finish his education and work in health care. He currently resides in an apartment in Edmonton, Alberta.

His lawyers filed a CA$20m wrongful imprisonment lawsuit against the Canadian government, arguing the government violated international law by not protecting its own citizen and conspired with the US in its abuse of Khadr.

The Supreme Court of Canada ruled in 2010 that Canadian intelligence officials obtained evidence from Khadr under "oppressive circumstances" – which included sleep deprivation tactics – during interrogations in 2003 and then shared that evidence with US officials.

The widow of Speer and another American soldier blinded by the grenade in Afghanistan filed a wrongful death and injury lawsuit against Khadr in 2014 fearing he might receive a payout.

A US judge granted $134.2m in damages in 2015, but the plaintiffs acknowledged there was little chance they would collect any of the money from Khadr because he lives in Canada.