Dissident republican inmates at Maghaberry Prison threatened staff that they would be murdered like their colleague David Black, the Justice Minister has said.
David Ford told the Assembly verbal threats made to staff referred to the 52-year-old prison officer who was gunned down on his way to work in 2012.
Following threats to staff, extra security measures were introduced within the prison, to the fury of republican prisoners who sparked a stand-off on Monday.
Around 40 inmates refused to return to their cells and officers were withdrawn from landings for their own safety.
They inmates have claimed that by introducing the new security measures, the Prison Service had failed to implement an agreement to relax security within the republican wing at Roe House.
Mr Ford said prisoners must "live up to their side of the agreement to ensure that they end intimidation within Roe House and intimidation of prison officers through social media and with external activities as well".
He added: "There are clearly issues from the agreement that was made almost five years ago that should see the prison running in a normal way, provided that there is appropriate behaviour on the part of prisoners. That is what is sadly lacking at the moment."
All visits to the jail were cancelled yesterday after a telephone bomb warning sparked a security alert outside the perimeter of the prison.
Amid ongoing concern over the safety of prison staff, Chief Constable George Hamilton has ordered a review of the policing of a 200-strong republican protest outside the jail on Monday night after a warder's car was attacked as he arrived for work.
The Justice Minister has also launched a probe into why Prison Service bosses had not warned the guard about the protest before his arrival at the scene.
"It should never have got to the situation where someone was able to drive into a hostile protest. That prison officer was left very shaken by his ordeal," said Policing Board member Jonathan Craig.
"I welcome that both the Chief Constable and the minister have both initiated reviews into what happened on Monday night."
The DUP MLA added: "This officer was placed in potential danger and measures need to be put in place to ensure something like this does not happen again."
Mr Craig also warned that the Prison Service was "losing control" of Roe House.
"What has been happening within the jail, not just in recent days, but in recent weeks and months, does not instil a lot of confidence that the prison authorities are in control of these prisoners. It is a very worrying situation," he said.
As the authorities attempted to manage the volatile situation at the jail yesterday, law firm Madden and Finucane threatened to launch emergency legal action, claiming lawyers were denied access to one of their clients, who was allegedly assaulted by staff during disturbances at the prison on Sunday night.
Solicitor Ciaran Shiels said that republican prisoner Christy O'Kane, who is charged in connection with a number of mortar attacks in the 1990s and IRA membership, was "one of a number of prisoners who were assaulted by riot staff on Sunday within Roe House".
Mr Shiels claimed that his client was denied access to his solicitor and a request for medical treatment.
He threatened High Court legal action against the Prison Service.
The Justice Minister rejected claims that an inmate had been seriously injured.
Sinn Fein MLA Raymond McCartney said that "no one wants to see an escalation of tensions in Maghaberry and the best way to improve the situation is to implement the August 2010 agreement between prisoners and prison authorities".
DUP MLA Paul Givan said Monday's incident was "an orchestrated attempt by republican prisoners so that they can get their demands met".
Story so far
On Monday prison management were forced to withdraw staff from the landings in Roe House, which contain dissident republicans, amid concern for their security after around 40 inmates refused to return to their cells. Republican prisoners claimed they were protesting against a failure by the prison authorities to keep their side of an agreement to relax security measures.