Several prison officers have been attacked during disturbances at two young offenders' institutions.
A woman prison officer suffered a fractured jaw in an attack at Moorland Young Offenders' Institution in Hatfield Woodhouse, near Doncaster.
There have also been disturbances at Warren Hill in Woodbridge, Suffolk, and all 138 inmates may have to be moved because a set of keys has been stolen.
The overnight incidents are not believed to be linked.
The Ministry Of Justice (MOJ) said a fight broke out at Moorland at 1900 GMT on Tuesday and 42 inmates refused to return to their cells.
An MOJ spokesman said: "Prison Service Tornado teams entered the prison at 1am.
"The prisoners offered no resistance. Several staff were slightly injured in incidents earlier that day and one prisoner suffered minor injuries during the incident."
He said 60 youths at Warren Hill refused to return to their cells on Tuesday night in a "totally separate incident".
After a stand-off Tornado teams were sent in at 0540 GMT and regained control, again with no resistance being offered.
The wing at Warren Hill is understood to have suffered extensive damage.
BBC home affairs correspondent Danny Shaw said it is thought prisoners got hold of a set of keys during the disturbances at Warren Hill.
As a result all the locks may have to be changed.
The acting National Chairman of the Prison Officers Association (POA), Tom Robson, said: "The street corner gangs re-associate inside our prisons.
"They continue in the only way they know which is in a violent and anti-social manner that our members confront and manage on a daily basis.
"Prison officers deserve the gratitude of the general public for the service they provide," he added.
The POA said the riot at Warren Hall was sparked when officers prevented some inmates from having unfettered access to the telephones and gyms because of bullying of other inmates.
The POA said: "They reacted with venom, causing significant damage to the prison and two prisoners being hospitalised with a number of staff injured whilst trying to deal with the riot."
The POA said it was the third serious incident this year at Warren Hill.