At least 28 people were arrested and several people injured after gardai turned two water cannons on anti-globalisation protesters who attempted to break through a security cordon on the Navan Road close to the Phoenix Park yesterday evening.
A live shotgun cartridge was later found lying on the Navan Road along with rocks, bottles and other missiles, which had been thrown at gardai.
Garda Superintendent John Farrelly defended the gardai's handling of the trouble. "We had a job to do. The job we had to do was to protect society, to protect the people in the park and the situation was that has been achieved," he said.
The crowds which had gathered in O'Connell Street later dispersed without any further trouble and calm returned to the city.
The trouble began yesterday evening shortly after 8.30 p.m. Within 40 minutes of the protest beginning hundreds of gardai on foot, members of the riot squad and mounted gardai pushed the protesters almost a mile away from the scene of the original disturbances - in the direction of the city centre.
There were a number of injuries during last night's disturbances and at least one female garda was brought to the James Connolly Memorial Hospital suffering from head wounds. Her condition is not described as serious.
The Indymedia website that the Wombles, who had indicated their intention to cause trouble at Saturday's protests, "appeared at front line" at 8.35 p.m.
A crowd waving a banner which read "No borders, no nations, against a Europe of capital" attempted to break through a cordon of plain-clothes gardai near the Phoenix Park's Ashtown Gate.
The plain-clothes gardai successfully prevented the group pushing through before the cordon before moving back behind a line of riot police.
Protesters - some of whom were wearing balaclavas - were reported to have thrown cans and sticks at riot police.
A spokesman for Another Europe is PossibleRory Hearne told ireland.comhowever that there was no provocation from the protesters and pointed out that the majority of today's protests were peaceful.
He blamed garda intimidation and heavy-handedness for the confrontation.
The protesters had taken a circuitous route to the site of the main celebrations to mark the accession of ten new states to the EU after they assembled at 6 p.m.at the GPO on O'Connell St.
Gardai use water cannon to subdue protesters gathered outside Phoenix Park Reporters being ferried from Farmleigh to the media centre in Dublin Castle yesterday were taken an alternate route in order to avoid the violent scenes.
Up to 1,000 people had gathered at Dublin's Heuston Station where a concert organised by Another Europe is Possible took place earlier yesterday.
A similar number of Reclaim the Streets protesters gathered in St Stephen's Green and marched through the city on their way to the GPO on O'Connell St.
The garda presence was said to be low-key and the atmosphere was widely regarded as good-natured.
The Heuston Station protest was addressed by activist Rory Hearne who congratulated the crowd "for facing down the intimidation" of the security operation. "We are here in our thousands and we have won today," he said.
A group of less than 150 protestors staged the first May Day protest in Dublin yesterday morning when they marched in glorious sunshine from the Civic Offices down the north Quays and through the city centre.
The protest stopped briefly on O'Connnell Bridge where protesters dropped a dozen carnations in the Liffey to mark the deaths of 12 non-EU citizens who died in recent times attempting to enter the Republic.
The group spoke against the creation of a Fortress Europe and called for a relaxation of immigration policies within the EU.
The Minister for Justice Mr McDowell came in for particular criticism for his immigration policies and the decision to hold a "racist" citizenship referendum in June.
Additional reporting PA