Prisons in Cameroon can be badly overcrowded
Guards have shot dead at least 16 prisoners during an attempted prison break in Douala, Cameroon.
Three other prisoners were captured and taken to hospital with injuries, the BBC's Randy Jo Sa'ah reports from the capital, Yaounde.
Inmates armed with guns had temporarily overpowered guards as they tried to launch the escape, our reporter says.
Cameroon's prisons are old and often overcrowded. It is the third attempted jail-break in three months.
Two armed prisoners cut electricity at the prison before trying to lead the escape, AFP news agency reported.
Human rights groups have described conditions in Cameroon's prisons as appalling and degrading, our correspondent says.
The prison in Douala, which was built in 1930, has a maximum capacity of 800 but holds almost five times that number, according to a Cameroonian human rights official.