THE HAGUE, Netherlands (AP) — The Yugoslav war crimes tribunal has rejected a request by one of the most senior Serb leaders during Bosnia's ethnic war to be released early from prison, citing the "very high gravity" of his crimes.

Former Bosnian Serb parliament speaker Momcilo Krajisnik was convicted in 2006 of persecuting and forcibly expelling non-Serbs during the 1992-95 war in Bosnia. His initial 27-year sentence was reduced on appeal to 20 years.

Including time spent in jail before his conviction, the former close ally of Bosnian Serb leader Radovan Karadzic has served more than 12 years of his sentence.

Krajisnik argued that in Britain, where he is serving his sentence, he became eligible for early release in April.

Tribunal President Theodor Meron's written decision was published Friday.