Nigeria's interior minister has ordered prison guards to "shoot to kill" those involved in jailbreaks.

Rauf Aregbesola made the comments in an address to prison staff in the southern city of Ibadan, saying anyone who attempts to breach security "must not live to tell the tale".

Over the past year armed groups have attacked various prisons, enabling more 5,000 inmates to escape.

A number of prison guards and detainees have also been killed.

Rights activists have expressed concern that the new policy may be abused by the security forces.

Nigeria's extremely slow judicial system means that about three quarters of almost 70,000 inmates are awaiting trial, according to the BBC's Ishaq Khalid.

The interior minister said this was partly responsible for the frequent jailbreaks.

Mr Aregbesola was speaking to senior officers at the Agodi Custodial Centre on Monday, where he said about two thirds of the 1,001 inmates were awaiting trial - in a facility designed to hold 400 prisoners.

Despite the overcrowding, he said the officers must make it impossible for anyone to penetrate prisons.

"Any effort to breach our facility is not acceptable. Don't shoot to injure, shoot to kill. Don't shoot to disable, shoot to kill," he said.

Jailbreaks are common in Nigeria as it continues to struggle with multiple security crises from kidnapping syndicates to an Islamist insurgency in the north-east.

In April last year, more than 1,800 inmates were freed by gunmen who ambushed Owerri police headquarters, in south-eastern Nigeria.

In September, 240 prisoners escaped after unidentified gunmen attacked a facility in Nigeria's Kogi state.