LONDON (AP) — A British court has shortened the sentence of a Royal Marine convicted of killing a wounded Taliban fighter in Afghanistan.

Sgt. Alexander Blackman was convicted of murder and sentenced to a minimum of 10 years by a military court in 2013 for the September 2011 killing in Helmand Province.

Footage from another marine's helmet camera showed Blackman shooting the militant in the chest at close range, then saying: "Obviously this doesn't go anywhere, fellas. I just broke the Geneva Convention."

Earlier this month, the Court Martial Appeal Court quashed the murder conviction and replaced it with one of manslaughter.

Supporters in the public gallery cheered Tuesday as the court reduced Blackman's sentence to seven years. He could be freed from prison within weeks, having served half his term.