KABUL - Mohammad Jawad, one of the youngest detainees to be held at the U.S. detention facility in Guantanamo Bay, Cuba, said on Tuesday after his return home to Afghanistan he had been abused and humiliated during six years in custody.

A teenager when he was held, he was accused of war crimes for throwing a grenade that wounded two U.S. soldiers in 2002, but was ordered freed in July by a U.S. judge who threw out his confession because it had been obtained through abuse.

He was one of the youngest detainees held at the prison. His lawyers argue that he was about 12 when he was arrested in 2002 but the Pentagon disputes that and has said bone scans indicated he had turned 18 when he was sent to Guantanamo.

Jawad's lawyers say he was kept awake, moved constantly from cell to cell and treated harshly.

He arrived back in the Afghan capital, Kabul, on Monday and was reunited with his family. Jawad was the latest departure from the controversial Guantanamo prison which President Barack Obama has pledged to close by mid-January 2010.

There was a lot of oppression when I was in Guantanamo and these inhumane actions were not for just one day, one week or one month, Jawad told Reuters, sitting on cushions in his family home in the south of the capital.

I was oppressed the whole time until I was released. They tortured prisoners very badly and did not allow prisoners to sleep, did not give enough food, he said.

Jawad was accused of throwing the grenade into a military jeep in 2002. He was arrested and imprisoned at the U.S. detention center at Bagram Air Base, north of Kabul, before being sent to Guantanamo in early 2003.

They knew I was underage but they did not care about my age, Jawad said.

They insulted our religion and our holy Koran, they insulted us and behaved in an inhumane way, he said.

A weary-looking Jawad stood and stretched his hands behind his back to show how he had been bound sometimes by his captors.

He said he and other prisoners were told to eat with their hands bound behind their backs, bending over and putting their mouths into plates of food.

Jawad said he had been freed because none of the charges against him could be proved.

I remember the U.S. government lawyer provided evidence against me but could not prove anything and in the end, the judge said: 'no charge against Mohammad Jawad can be proved and he is innocent', Jawad said.

(Additional reporting by Yousuf Azimy; Editing by Paul Tait)