The Prison Officers Association claims two officers were assaulted during the incident at HMP Lindholme.
It is not known how many inmatesÂ were involved in the violence but the POA claims prison officers '˜face a daily battle to maintain order and discipline' at the jail.
The POA said staff '˜genuinely feared for their safety this morning' and refused to enter the prison until '˜safety assurances and plans were put in place'.
The POA claims inmates involved in the attack had to be placed back into their own cells overnight because the prisons' segregationÂ unit was already full.
ItÂ is claimed thatÂ the violence '˜follows a number of serious assaults' at the prison and that bothÂ staff and inmates are '˜at risk' there.
Mark Fairhurst, chairmanÂ of the POA, said:Â 'I had to call Her Majesty's Prison and Probation Service Chief Operating Officer, Phil Copple, this morning to ensure my members had a safe place to work.
'While I was doing this the Governor was ordering staff to commence a full unlock.
'Thankfully following interventions from senior management discussions are ongoing to ensure Lindholme can operate safely.'
=Steve Gillan, general secretary of the POA said: 'The Government and HMPPS must listen to staff and accept that our prisons are in crisis. The latest prison ratings prove that the concerns the POA has consistently raised are not being addressed.
'We have called for a back to basic approach to ensure security, safety and control are the priority of the service.
'Unfortunately, local management are being given the licence to do as they see fit and this often leads to unrest, violence and disorder. Things have to change.'