The government in Kigali denies that any extrajudicial killings took place.
Most of the alleged victims were accused of theft – in one case stealing bananas.
Others were accused of smuggling marijuana, illegally entering the country, or using illegal fishing nets.
Human Rights Watch says the executions took place between July 2016 and March 2017 in western Rwanda.
They believe it is part of an official strategy to “spread fear, enforce order and deter any resistance to government orders or policies”.
Witnesses told HRW the fate of one man, accused of stealing a cow, was decided in a community meeting. Fulgence Rukundo was questioned about the stolen cow, then taken to a community meeting with the district mayor.
One witness described what happened next:
“When the meeting was finished, the soldiers walked Fulgence to a small field near a banana plantation. There were many of us following; some were primary students.
We wanted to see what would happen… A soldier told him to stand up and walk, and another soldier told us to leave. At that moment, I heard three shots.”
The report by HRW also alleges that, in another case, two men were killed by civilians after local officials encouraged them to do so.