Guyanese officials say gunmen went on a shooting rampage in the village of Lusignan, killing 11 people.
Saturday's massacre is the country's worst violence in recent years. Officials say five children were among those killed. It is not clear why the victims were targeted.
President Bharrat Jagdeo denounced the massacre and met with security officials to discuss the situation.
The attack occurred hours after gunmen attacked police headquarters in Guyana's capital of Georgetown, wounding two officers.
On Wednesday, gunmen attacked soldiers from the Guyana Defense Force who were on patrol near the capital. One soldier was killed and another was wounded.
The attacks followed threats from suspected gang leader Rondell Rawlins, who has accused security forces of kidnapping his pregnant girlfriend.
Some information for this report was provided by AFP and AP.