Prison authorities have ordered a lockdown on the dissident republican wings at Maghaberry Jail over fears that a protest could escalate.

Prisoners were informed of the 72-hour lockdown in a memo delivered to their cells on Tuesday morning.

It is claimed the measure could be extended by a further 28 days if they do not comply with an earlier evening lock-up time.

Speaking to the Belfast Telegraph, a dissident leadership source said "a slow-motion train crash" was happening inside the prison — and warned of consequences outside the jail.

In a sinister threat in March, the group Oglaigh na hEireann (ONH) told this newspaper it had the personal details of a number of prison staff "up to and including governor level".

The jail protest is about a number of issues — strip searches, lock-up times and freedom of movement inside Roe House, where on two landings more than 30 dissident prisoners linked to a number of groups are held.

These include the Real and Continuity IRA organisations and ONH.

Some of those prisoners are now involved in a so-called dirty protest.

Others have been involved in "hand-to-hand fights" with prison officers in recent days.

Attempts by facilitators, who brokered an agreement between prison chiefs and prisoners last August, to gain access to the prison have "failed up to this point".

Commenting on the developing protest, a source said: "The prisoners have ruled nothing out."

He did not elaborate on that comment, but added: "This could all be resolved by the Prison Service."

The source claimed what was happening was "an attempt to use the prison as a breaker’s yard", and said: "The agreement (last August) is opposed by a large section of the Prison Officers Association."

A spokesman for the Department of Justice told the Belfast Telegraph: "The Northern Ireland Prison Service can confirm that following non-compliance with lock-up times, a number of prisoners have been placed under Rule 32, which restricts their association."

He added: "In line with agreed procedures, this will be reviewed within 72 hours."