An investigation is under way at Oberstown youth detention centre in Co Dublin following incidents in which one staff member was injured and a rooftop fire broke out at the facility.

A number of detainees managed to take control of a residential unit after a set of keys was taken from a staff member yesterday afternoon.

One staff member was injured as they tried to bring the situation under control.

Five detainees managed to escape from that unit and were joined by three other teenagers. All eight then gained access to the roof.

A fire began on the roof at around 8pm last night. The blaze caused extensive damage to Unit three at the complex.

Speaking to RTÉ's Morning Ireland, Oberstown director Pat Bergin said several teenage detainees had staged a rooftop demonstration at the facility earlier in the day, before lighting a fire.

Dublin Fire Brigade said that at one point there were six units at the scene.

A garda investigation is under way into the cause of the fire.

The situation began to escalate around 1.30pm and campus Director Pat Bergin said there was minimum staff cover yesterday due to strike action.

The strike action by staff protesting against working conditions continued until 4pm.

Mr Bergin said as soon as the situation got out of control their critical incident management team was mobilised and a number of staff came to their assistance from the picket line.

The incident management team consists of gardaí and other services.

The Garda Emergency Response Unit, the Fire Service and ambulances all attended the scene.

Responding to the disturbances, Minister for Children Katherine Zappone, said she has requested a report on what happened and is "determined to move forward".

She said she is determined to act on any recommendations made in the report.

Ms Zappone called on the staff, the management and the unions to resume discussions to resolve their industrial relations dispute as soon as possible.

Asked about the use of the Emergency Response Unit at the centre last night, she said the response last night was "appropriate".

Meanwhile, SIPTU and IMPACT trade unions have said the new expanded campus is badly designed to deal with vulnerable young people and violent offenders.

Attempts to resolve the dispute at the Work Relations Commission have so far proved unsuccessful.

The unions have served notice for three further stoppages next month on 5, 12 and 19 September.