Inmates at Lebanon's largest prison rioted briefly on Tuesday, setting their clothes and mattresses on fire and leaving several prisoners injured, Lebanese security officials said.
The officials said 18 prisoners at the Roumieh prison east of Beirut suffered from smoke inhalation and minor burns from the fire.
They said 10 of them were taken to the prison's medical ward while eight were rushed to hospitals outside the compound under tight security.
The officials said police reinforcements and fire engines were sent to the compound to extinguish the fire and put the situation under control. They said calm was restored shortly after the riots started but gave no further details.
The officials spoke on condition of anonymity because they were not authorized to talk to the media,
The prison compound houses four high-profile detainees _ former generals held in connection with the 2005 assassination of former Prime Minister Rafik Hariri _ as well as members of the al-Qaida-inspired Fatah Islam militant group.
The generals have been in detention since August 2005 and have not gone on trial yet. The security officials said the four are held in a building far from the actual scene of the rioting and were unhurt.
Prison riots are not uncommon in Lebanon, where inmates often demand better conditions and reduced sentences.
The officials said some of the prisoners who took part in Tuesday's rioting were asking authorities count a year in prison as eight months instead of 12. They also said that several prisoners suspected of being behind the riot would be investigated on charges of endangering the lives of other inmates.
Tuesday's rioting was the worst since prisoners took seven policemen hostage in Roumieh last April. In January, prisoners rioted in north Lebanon's largest prison. Both riots ended without casualties.
Roumieh prison was build four decades ago to house 1,000 prisoners but today has more than 3,000.