Nine inmates were killed in a botched prison break in the Democratic Republic of Congo on Sunday after one of them pulled the pin on a grenade but didn't throw it, a police official said.
The incident follows a rash of prison violence and escapes in the central African country, including the escape of nearly 1,000 detainees from a high security jail in September.
"The civilian (prisoner) did not know how to use a grenade, he pulled the pin out but didn't throw it," the provincial chief of police, General Gaston Luzembo, told Reuters.
He said 50 people were wounded in the incident in a prison in the eastern city of Bukavu, and that an investigation was looking into how the inmate had got the grenade.
Luzembo added that a jailed ex-colonel appeared to be among the masterminds of the attempted escape.
A Reuters witness said the early morning blast at the jail was followed by gunfire and some inmates who had suffered serious injuries were being treated at a local hospital.