A Congolese warlord convicted of using child soldiers has appealed to the International Criminal Court for early release from his 14-year sentence, saying he wants to go to university to research the causes of ethnic conflicts.

Thomas Lubanga, the first person convicted by the court, deployed children in a brutal conflict in the eastern Ituri region of Democratic Republic of Congo in 2002-2003.

His lawyers argued Friday that Lubanga has been in custody — including time spent incarcerated before and during his drawn-out trial — for more than 12 years and he is eligible for early release after serving more than two-thirds of his sentence.

Prosecutors have urged judges not to release him, saying he allegedly has been interfering with witnesses in another case.