WARNING: GRAPHIC CONTENT
British runners have described the 'state of chaos' in Boston in the aftermath of two blasts which killed three people and injured 140 more.
Almost 350 of the 25,000 runners in the Boston Marathon were British - with many caught up in the immediate blast which rocked the finish line of the event yesterday.
Several Britons told of the 'frightening scene' after the double blast, which happened shortly before 3pm local time in Boston.
Abi Griffiths, from London, crossed the finishing line around 10 minutes before the "chaos".
The 34-year-old told Sky News she heard the explosion while collecting her bag.
"The ground shook and immediately people sort of looked around - it was just too loud to be something that wasn't serious," she said.
"People kind of didn't know what to do. Then all of a sudden it went into a state of chaos.
"Police were everywhere, we were being evacuated out of the area and it was really eerie.
"It was very, very scary and what should be a major celebration of the achievement of running 26.2 miles suddenly became a frightening scene."
She said police had swung into action quickly.
"This is just such an awful scene to have happened," Ms Griffiths continued. "It felt like it may have come from the inside of a shop.
"Suddenly you looked around and there was this cloud of smoke and then people went into gear. There were police everywhere."
Two-time winner of the Boston marathon Geoff Smith, originally from Liverpool, told ITV Daybreak from Boston: "It was surreal.
"One minute you've got the enthusiasm of everybody here - it's a family event, there's a great deal of excitement.
"As soon as we saw the explosion on TV the entire restaurant went silent, it was like being in a church. It was just spooky.
"It's really sad and takes a piece of you away but you can't let it get to you and you've got to think of the future and what we are going to do to rectify it.
"We've got to continue with our lives and we've got to continue with our sport.
"It's message to everybody out there - we've got to be vigilant, we've got to be watching every person around us."
Jez Hughes, a firefighter from Morley, west Yorkshire, was walking to the subway with his wife when they heard two explosions.
He had been standing only 100 yards from the finish line with other competitors after completing his 10th marathon but walked around the corner to meet his wife.
"While we were going to the subway we heard two explosions. I said straight away that sounds like a bomb and then we heard a second one," Mr Hughes, who was running for The Fire Fighters Charity, said.
"My wife is very shook up but we are out here until Thursday evening and no terrorists are going to spoil our day, don't let them get the better of you.
Darren Foy, 40, from Southampton, his wife Sandra and their two children, missed the explosions by just half an hour after he finished the marathon in three and a half hours.
The chartered surveyor, who is chairman of the Lordshill Road Runners in Southampton and was competing in his fourth marathon, said: "There are reports here that the explosions came from a hotel at the finish line and I walked past there a few days ago to pick up my race number.
"It's such a soft target. There are hundreds of thousands spectators on the streets and 27,000 runners, so we got off lightly."
Mark Jenkin, a 34-year-old sports writer from Barnstaple in Devon, said the explosion had put the race into perspective.
After finishing 138th in a time of 2 hours 24 minutes, he told his paper, the North Devon Journal: "It's a beautiful spring afternoon in Boston. The people of the city put on a great race and it's such a tragedy this has happened.
"I was feeling tired and a bit disappointed with my time in the race but all that seems irrelevant now. I just feel grateful to be ok."
Chris Bird, chief executive of Sports Tours International, which organised for 51 people to go to the Boston Marathon - 40 runners and 11 non-runners - said all were accounted for.
"We spoke to every single one, the team back at the office, in the incident room, spoke to families and to runners that we could get hold of and our team on the ground in Boston spoke to everybody and checked them all into the hotel," he told BBC Breakfast.
"Thankfully everybody is safe."
Some runners travelling with his company completed the race, but most had been been pulled off the course to safety after the blasts took place, he said.
"They were pulled off the course and were really just pulled away from any area of danger or potential danger and needed then to make their own way back to their hotel," he said.
"Over 300 British people ran the Boston Marathon and the majority will have run for a cause either close to their hearts or close to colleagues or they will be raising money for some sort of good cause. So it means a lot to everybody and the emotions attached to it are really high.
"Something like this really focuses the mind on what is really important."
Susanna Reid, the BBC Breakfast presenter who is running in the London Marathon, said: "I ran the London Marathon last year - you have such a sense of community with everybody else running and I think that is going to be so reinforced this Sunday.
"There is going to be definitely a different atmosphere about it."
Anthony Meenaghan said he was "safe and well" but added "can't believe what I saw and heard".
Mr Meenaghan, 21, is an architectural technology student from Sheffield Hallam University who is on a work placement in Boston. He was running with his father, who is also called Anthony.
He tweeted: "Thanks for all messages. I'm safe and well. Can't believe what I saw and heard. Sad day."
His mother, Tracy Mumford tweeted: "My son Anthony Meenaghan and his dad were running the Boston Marathon today for charity xxx i thank God they are both safe!!!"
Mr Meenaghan is from Bingham, near Nottingham.