Prosecutors at the International Criminal Court argued in summing up Tuesday that two Congolese ex-militia leaders are guilty of a bloody massacre of villagers that claimed more than 200 lives.

Germain Katanga, 34, and Mathieu Ngudjolo Chui, 41, face war crimes and crimes against humanity charges over the 2003 attack in the Democratic Republic of Congo's mineral-rich northeastern Ituri province.

If found guilty, they could face up to 30 years in jail or, if judges deem the case particularly severe, life behind bars.

The two men listened impassively as deputy chief prosecutor Fatou Bensouda recounted witness testimony on how "victims were burnt alive", "babies were thrown against walls" and women were forced to serve as sex slaves.

The two former commanders are also accused of using child soldiers in their ethnic Lendu and Ngiti-based rebel armies which attacked civilians and fought against militias of the Hema tribe.

In the first day of summing up, Bensouda said: "The evidence all points to one thing... Germain Katanga and Mathieu Ngudjolo Chui are guilty beyond reasonable doubt of the crimes imputed to them."

More than 200 people in Bogoro village were killed within hours in the February 24, 2003 onslaught.

Prosecutors described how the men's militia was organised and under the control of Katanga, and the prosecutor said the attack on Bogoro "was not an isolated fact, it is part of a conflict on a grander scale."

Ethnic clashes for control of Ituri started in 1999, and non-government groups say more than 60,000 people died in the conflict, the court heard.

Bensouda recounted that "prosecution witnesses also described how the plan (to attack Bogoro) was designed and how the defendants attended meetings preceding the attack".

Both men have pleaded not guilty to the charges in their combined trial which started on November 24, 2009.

The men's defence will take the stand next Monday and Tuesday.