The gunmen were dressed in military uniforms and took weapons from a police station in Bartica, 80 miles (130km) south-west of the capital Georgetown.

The attack is the second blamed on gangs in recent weeks.

On 26 January, 11 people - including five children - were killed when gunmen attacked the village of Lusignan.

At least six gunmen arrived in Bartica late on Sunday by a speedboat on the Essequibo River and attacked the town's police station, regional official Hilbert Knights said.

'Attacked in bed'

Health Minister Leslie Ramsammy said nine of the civilians killed included five people who were sleeping in hammocks alongside the river, outside Bartica's police station.

The town of 15,000 people is a supply centre for miners prospecting for gold and diamonds in the country's interior.

Police believe that Guyana's most-wanted man - alleged gang leader Rondell Rawlins - is responsible for the January killings in Lusignan.

He has accused the authorities of kidnapping his 18-year-old pregnant girlfriend and has promised to carry out further attacks.

Authorities have offered a reward of $150,000 for the capture of Mr Rawlins, who is also wanted over the murder of a government minister in 2006.