About 100 demonstrators circled the front gates of the US embassy carrying placards with the slogans "Stop Bush's war," "No bombing of Afghanistan," and "Negotiate not annihilate".
The embassy was closed yesterday for Columbus Day, a US holiday, but as US security personnel stood behind the gates, speaker after speaker decried the military strikes on Afghanistan and condemned President Bush and his father, who gave the order for the 1991 strike against Iraq.
Protesters also criticised the Irish government and said it would have the blood of all the people killed in the attacks on its hands.
Mr Kieran Allen, the official spokesman for the newly established Irish Anti-War Movement, called on the Government to dissociate itself from the military action by US and British forces, and to forbid refuelling at Shannon and to close its airspace to US military aircraft.
He said: "The bombing of half-starved people and the destruction of what little infrastructure exists in Afghanistan is a human rights tragedy. It is immoral to punish the people of Afghanistan for the September 11th atrocity."
The Irish Anti-War movement was established just a fortnight ago from a meeting of the same and other pressure groups.