108 Irish citizens 50 of whom were listed as residing in Ireland had registered to take part in the event. All of those have now been accounted.

3 people were killed including an 8-year old local boy in the blasts while more than 140 others were injured. 17 of those are believed to be in a critical condition.

The blasts happened within seconds of each other. It is thought some of the runners who were heading towards the finish line had turned back right into the path of the second explosion.

The President Michael D. Higgins and the Taoiseach have expressed their sympathies to the victims and their families.

Enda Kenny has described the bombings at the Boston Marathon as an act of insanity. And he expressed his hope that the people responsible for the explosions that killed three and injured around 140 people will be brought to justice as soon as possible.

Speaking on his way into Government Buildings this morning the Taoiseach said he met with the Governor of Boston last year and will welcome him to Ireland on a trade mission next month.

The Tanaiste and Minister for Foreign Affairs, Eamon Gilmore issued this statement:

"My thoughts are with the people and the authorities in Boston as they continue to deal with this tragic situation", the Tánaiste said. "I know that there were a significant number of Irish participating or involved in the Marathon, and my Department - in particular the Irish Consulate in Boston - is doing all that it can to make contact with our nationals to check on their situation. So far, fortunately, all have been safely accounted for. However, the situation is still developing and I would ask any family who may be concerned for loved ones that they have not heard from and who might have been present in the area to contact my Department at 01-408 2000."

Mr Gilmore said he received a report on the situation as soon as the attack occurred.

The Fianna Fail leader Michael Martin has also extended sympathy to all those affected by yesterday's events.

The FBI has now taken charge of the investigation into the double attack on the Boston marathon. It is understood there are no suspects and as of yet there is no clear motive.

US President Obama has pledged all resources in the efforts to bring those responsible for the attack to justice. Obama says those responsible will feel the "full weight of justice".