Hundreds of mourners convened on a bridge on River Akagera in Ngoma District to commemorate thousands of people dumped into the river during the 1994 Genocide against the Tutsi.
River Akagera serves as the borderline between Ngoma and Bugesera districts and some of the victims that were thrown into the river during the Genocide ended up in Lake Victoria in Uganda and turned up on its shores.
Uganda hosts three memorial sites that house the remains of those victims.
Callixte Kabandana, a representative of the Genocide survivors association in Rukumberi (ARGR), said they attach value to taking time to remember slaughtered loved ones who were thrown into the river - some of the them still alive before drowning.
Very few managed to swim across the river and survived. Kabandana is one of them.
"For anyone thrown into this river, the Interahamwe militia knew there was no escape, that is even why many were thrown in alive," he said.
Many drowned while others, he said, were devoured by reptiles.
"The seemingly calm waters claimed so many of our loved ones 24 years ago," he said.
Many Tutsi were also killed on the bridge before their bodies could be thrown into the river, he said. "There was a roadblock of the Interahamwe right on this spot; no fleeing Tutsi could go past it. They were killed mercilessly."
Kabandana said survivors treat the bridge as a memorial site. "We come here every year to honor the memory of the victims."
Rukumberi is sandwiched between several lakes - Mugesera, Sake, and Birira - and River Akagera, and this made it even harder for Tutsi to escape during the killings.
Close to 40,000 Tutsi were killed in Rukumberi during the 1994 Genocide against the Tutsi.
The event was organised by Rukumberi Genocide Survivors Association in conjunction with Ngoma District officials and Eastern Province authorities.