Martin Richard pictured: 8-year-old Boston Marathon victim was waiting at finish line to give his father a hug

Martin Richard, an 8-year-old boy waiting at the Boston Marathon finish line to give his father a hug, was among three people killed and more than 144 injured in the two explosions.

Martin Richard was standing with his mother and sister, who both suffered horrific injuries when bombs hidden in rubbish bins exploded within seconds of each other during the Patriots’ Day bank holiday.

Boston police closed off the city as a “danger zone” as witnesses described the “unspeakable horror” of body parts flying through the air and shoes that “still had flesh in them”.

At least 17 of the injured people are in a critical condition and it is thought as many as 30 victims may have needed amputations or major corrective surgery on maimed limbs.

Today, the US remained on full alert after the worst terrorist outrage since the World Trade Centre towers were destroyed by hijacked jets on September 11, 2001.

President Barack Obama vowed to hunt down the culprits and “hold them accountable”.

In the UK, Scotland Yard confirmed security arrangements were being reviewed ahead of Margaret Thatcher’s funeral on April 17 and London Marathon on April 21.

Video footage showed an explosion going off in the heart of the crowd that had lined the streets of the Massachusetts city yesterday to watch the famous sporting event.

After the blasts, two more suspicious devices were found in the city’s Mandarin Oriental and Lenox hotels. Both were evacuated and the suspected bombs dismantled.

According to the Boston Globe, Martin Richard, from Dorchester, Massachusetts, may very nearly have cheated death after walking out to embrace his father Bill Richard as he went to cross the finishing line.

When his walked on, Martin Richard turned back to rejoin his mother and two of his siblings just as the first bomb exploded. Reports suggest his mother was seriously injured and his sister’s leg was blown off.