A core group of activists confronted officers outside the Dail after a demonstration in Dublin to protest about a proposed austerity budget. More than 50,000 people took to the streets under the banner of the Irish Congress of Trade Unions to demand a better and fairer deal.
Gardai said the protest passed peacefully, with no arrests, but after the march hundreds of activists broke away and marched to the parliament, where masked men also set fire to an election poster of prime minister Brian Cowen.
The march followed news of an 85 billion (72bn) rescue package to bail out the Irish banks and details of a four-year recovery plan. Measures include cutting the minimum wage and 3bn in welfare cuts.