THE HAGUE (Reuters) - Prosecutors appealed to a United Nations court in the Hague on Tuesday to expand findings of guilt against former Bosnian Serb leader Radovan Karadzic to include a second genocide conviction, for killings of Croats and Muslims in towns across Bosnia during the 1992-95 war.

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They also appealed to judges to increase his 40-year prison sentence.

Karadzic, 72, was found guilty in May 2016 of 10 charges including war crimes, crimes against humanity -- and genocide for the 1995 Srebrenica massacre, in which about 8,000 Bosnian Muslim men and boys were killed by Bosnian Serb forces.

But he was acquitted on a second charge of genocide related to attacks on Muslim and Croat populations in other parts of Bosnia.

Karadzic’s appeal against the conviction opened on Monday at the International Residual Mechanism for Criminal Tribunals (MICT), which took over cases from a U.N. court for the former Yugoslavia when it closed last year. He said he was innocent and asked for a retrial.

Prosecutors on Tuesday appealed his acquittal on the remaining count, saying in their opening statement that Karadzic played an “essential and leading role” in atrocities.

“(Karadzic) abused his immense power to spill the blood of countless victims. Justice requires that he receive the highest possible sentence, a life sentence,” Katrina Gustafson told the judges.

Karadzic, the political leader of the breakaway Bosnian Serb Republic during the war, told the court: “Nothing that is alleged in these proceedings is true.”

He said the Bosnian Serbs had acted defensively in the war.

The original trial judges had ruled that prosecutors fell short of the proving genocide, which would have required showing an intent to destroy Muslim and Croat populations, rather than merely slaughtering many to drive them out.

In their appeals arguments, prosecutors insisted that Karadzic knew the levels of violence needed to carry out “ethnic cleansing” policies amounted to genocide.

“Karadzic and his associates knew that they would need to spill rivers of blood to carve out the ethnically-cleansed territories they sought and embraced this bloody path,” Gustafson said.

A verdict is expected by the end of the year.

(In paragraph two, this story removes reference to 10 counts of genocide; in paragraph three, changes “10 counts of war crimes” to “10 charges including war crimes, crimes against humanity -- and genocide”, and removes reference to Sarajevo for clarity.)