Mrs Ireland, originally from Unanderra, was two blocks away when the first explosion occurred.

‘‘At first I thought it was a car crash but there were no cars in the city,’’ she told the Mercury from her hotel.

‘‘I knew it wasn’t a gun shot, it was too big and heavy, my friend described it as sounding like big claps of thunder.

‘‘It started to get chaotic with people running all over the place and the volunteers were directing people out of the city.

‘‘It was when I saw the choppers above us that I realised something big had happened.’’

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Mrs Ireland’s husband, Jonathan Ireland, originally from Dapto, had finished the marathon in three hours and five minutes so had cleared the finish line well before the explosions occurred.

The couple returned to their hotel so Mr Ireland could shower and were on their way back to the finish line to see friends complete the race when the bombing occurred.

‘‘One of our friends was still running, she’s fine but it took a couple of hours to find her,’’ Mrs Ireland said.

‘‘(The competitors still running when the bombs exploded) were stopped.

‘‘My friend was at the 25 mile mark, about one mile from the finish. They bussed them out.’’

In the aftermath of the explosions, Mrs Ireland said the marathon medical tents were turned into makeshift triage hospitals and there were ambulances everywhere.

‘‘(Authorities) found two more devices which they detonated, that makes me anxious,’’ she said.

‘‘They’ve brought in the army, there’s police, I heard they brought in navy bomb guys.’’

Mrs Ireland said she and her husband would now decide whether to leave Boston earlier than planned to continue their holiday or stay in the city.

‘‘We’ve heard the airports are in lockdown, they’re doing thorough searches of aircraft,’’ she said.

‘‘They’re upping security, although I have no idea how you do that in America. 

‘‘It will be chaos for the next few days.’’