Self-inflicted deaths and self-harm rates in Welsh jails have soared in the past four years, official figures have shown.
In 2013, there was one death of this kind in the four Welsh prisons but this rose to seven by 2016.
Rates of self-harm on average rose by more than three times in the same time period.
The Howard League for Penal Reform said suicide rates across English and Welsh jails had more than doubled since 2013.
In Wales, Swansea and Parc Prison in Bridgend both had three self-inflicted deaths in 2016 after none in 2013, while Cardiff had one in each year. Usk/Prescoed had none in both years.
Rates of self-harm rose from 440 to 1,452 in Parc, 43 to 201 in Cardiff and 34 to 149 in Swansea.
Usk had none in 2013 but 29 in 2016.
Assaults on staff
Parc Prison also had one of the highest rate of prisoner-on-prisoner assaults in the UK, at 641 in 2016.
Frances Crook, chief executive of the Howard League, said: "These latest figures on safety in custody are unutterably terrible.
"It is frankly shameful that such human misery under the supposed care of the state is allowed to continue in the 21st century.
"The general election is only six weeks away and the political parties must address this crisis directly. By taking bold but sensible steps to reduce the prison population, we can save lives and prevent more people being swept away into deeper currents of crime and despair."
The number of assaults on staff in Wales has also more than doubled over a year, compared to by 40% across England and Wales.
The vast majority of Welsh incidents were in Parc Prison, which saw 245 attacks on officers, the second highest number of all prisons in the UK. Only Birmingham which saw riots last December had more incidents.
In Cardiff there were 86 assaults on staff, up from 33 the previous year, while Swansea saw another big rise, with 50 assaults in 2016 compared with 15 the previous year.
Usk Prescoed remains one of the safest prisons for officers with just one incident reported in 2016 and in 2015.
The Ministry of Justice said it was unable to comment during an election period but issued some information on custody safety.
There has been a decrease in all types of assault during the most recent quarterly figures.
Total assaults fell by 4%, while deaths in the most recent quarter across the UK are down compared to the three-month period from October to December 2016.