One Garda was hospitalised and two others injured during an anti-lockdown protest on Saturday.
Riot police were called after violent clashes in the capital led to 23 arrests.
Taoiseach Micheal Martin condemned the “thuggish behaviour”.
There were shocking scenes in Dublin city centre on Saturday as far-right anti-lockdown protesters clashed with gardai.
Three officers were injured – one was hospitalised.
Around 125 gardai – included mounted police and dog handlers – were called in to prevent demonstrators from getting into St Stephen’s Green in a bid to block demonstrators from entering the park.
With their path blocked huge crowds formed on Grafton Street where a police cordon was put in place to keep the protesters at bay.
Video footage showed ugly scenes during a tense stand-off as protesters threatened to breach the blockade.
Disturbing images showed one person in the crowd walk up to gardai and fire fireworks from a tube directly at officers at point blank range.
A number of skirmishes quickly broke out as gardai moved to disperse the crowds.
Shameful scenes saw thugs tear down barriers while fireworks, flares and bottles were also hurled at Gardai and officers spat at amid the vicious clashes.
Others could be seen holding signs carrying anti-vaxx sentiment and Irish flags.
At least 23 people were arrested and a number of people charged last night at a special sitting of Dublin District Court.
Luas operator Transdev was forced to suspend Green Line services at St Stephen’s Green during the afternoon as a result of the protest.
A senior Garda told the Irish Sunday Mirror: “These are serious far-right extremists who are behind this.
"They are a well organised network willing to use violent means to achieve their aims.
"The organisers are a threat to the very institutions of this state.
"They have made threats online – they have the capacity to carry out their threats."
Taoiseach Micheal Martin, on Saturday night condemned the “thuggish behaviour” and praised gardai for their response in restoring order.
He said: “The large gathering, in the face of ongoing Covid-19 restrictions, showed a complete lack of respect to the people who have made huge sacrifices during this pandemic.”
In a statement A Garda statement revealed that 125 officers, including uniformed and plain clothes officers, public order units, the Garda Mounted Unit and Dog Unit, were deployed.
It added: “During the course of the operation further resources were redeployed in support.
“The gathering became violent on occasions with members of An Garda Siochana targeted with fireworks, missiles and spit. Gardai were forced to intervene. A number of those arrested were last night charged at a special sitting of Dublin District Court.
Garda Commissioner Drew Harris, right, said: “This was a protest that sits outside the normal behaviours of our society.
“These are not mainstream groups, the majority of society are compliant with the regulations and are living within these regulations in order to supress Covid-19.”
Justice Minister Helen McEntee aid: “I have spoken to the Garda Commissioner this evening and he has told me the disturbance in Dublin is being brought under control.
“I know there have been a number of arrests already today and a special court sitting is being arranged to make sure these law-breakers are prosecuted speedily.
“This situation was completely unacceptable and was an insult to so many who have worked so hard in the fight against Covid-19 and to those who have died.
“This mindless thuggery showed a wilful and blatant disregard for the public health rules which are needed to help us all and keep us safe.”
The clashes come as Gardai warn of house checks for people entering the State who are reported as not engaging with the Department of Health’s monitoring process.
Mandatory quarantine rules are set to be introduced in the coming weeks.
