Judges at the International Criminal Court Tuesday sentenced former Congolese vice president Jean-Pierre Bemba to 18 years in jail for a series of brutal rapes and murders in Central African Republic over a decade ago.

"The chamber sentences Mr Jean-Pierre Bemba Gombo to a total of 18 years of imprisonment," said judge Sylvia Steiner, ruling that the former militia leader had failed to exercise control over his private army sent into CAR in late October 2002 where they carried out "sadistic" rapes, murders and pillaging of "particular cruelty."

Bemba, 53, was found guilty in March of five charges of war crimes and crimes against humanity committed by his private army called the Congolese Liberation Movement (MLC), which he sent to neighbouring CAR from October 2002 to March 2003 to put down a coup.

READ: ICC finds Congolese politician guilty of Central African war crimes

Prosecutors at the ICC had called for a minimum 25-year jail term in the landmark case, the first to focus on rape as a weapon of war by the ICC, which was set up in 2002 to try the world's worst crimes.

But just hours before the sentencing, Bemba's defence team gave notice late Monday that he would appeal his conviction.

"The appeal will not be limited... to criticism of the trial chamber's findings, but will also allege that in material respects the whole trial process was flawed and unfair and that Mr Bemba's rights as an accused were violated throughout," defence lawyer Peter Haynes said in a filing to the court.

"No reasonable trial chamber could have convicted him of the charges he faced," Haynes argued.

The trial judges erred because they had "misinterpreted and/or misapplied the law and took an unjustifiable approach to the evidence," he added, arguing that "there was a mistrial."

The judges found in their March 21 verdict that the former Congolese vice president turned a blind eye to a reign of terror by some 1,500 of his troops, sent to the CAR to prop up then president Ange-Felix Patasse.

Despite knowing what was happening, Bemba "failed to take all necessary and reasonable measures to prevent" a litany of crimes, which included the gang rapes of men, women and children, sometimes as their relatives were forced to watch, the judges said.

As well as the issue of rape as a weapon of war, the Bemba case is also the first at the ICC to focus on a military commander's responsibility for abuses by his troops, even if he did not order them.

Bemba will now spend ten years behind bars having already spent eight years since his arrest in 2008.

Key highlights in Bemba's political life

• 1998: Helped by Uganda to form MLC rebel group
• 2003: Becomes DR Congo's vice-president under peace deal
• 2006: Loses run-off election to President Joseph Kabila but gets most votes in western DR Congo, including Kinshasa
• 2007: Flees to Belgium after clashes in Kinshasa
• 2008: Arrested in Brussels and handed over to ICC
• 2010: Trial begins
• 2016: Found guilty of war crimes and crimes against humanity and handed 18 year sentence

- BBC