Boston Marathon bombings survivor Rebekah Gregory crosses finishing line on prosthetic leg

She had her lower leg amputated after being injured in the explosions

Rebekah Gregory crosses the finishing line of the Boston Marathon two years after she almost died in the bombings (YouTube)

This was the emotional moment Boston Marathon bombing survivor Rebekah Gregory crossed the finishing line where she almost died two years ago.

The 28-year-old completed the final three miles of the race on Monday on a prosthetic limb after her left leg had to be amputated below the knee.

Last year she crossed the line in a wheelchair in a “tribute walk” and the feeling of doing it running yesterday made her fall to her knees “overcome with emotion”, she said.

Mrs Gregory wrote on Facebook that it was the day she “took her life back” after two years of pain, surgery and rehabilitation.

“It is extremely emotional…to remember what it felt like to be bleeding out on the pavement, wondering if I would ever see my child's smile again,” she said.

“In a matter of minutes, my entire world changed. Everything I knew was literally blown to pieces, and I was forced to start picking them up one by one.”

She said she thought she was going to die on the pavement on Boylston Street, where three spectators were killed in the explosions.

Rebekah Gregory, 28, said she had 'taken her life back' by running the final part of the race (Facebook)

“This time I won't be laying on the ground in pieces, or having to be assisted because I can't do things on my own,” Mrs Gregory wrote ahead of the race.

“This time the only thing hitting the ground will be my running shoe, as I show myself and the rest of the world that I am back, stronger than ever, and there is no stopping me now.”

After undergoing numerous operations, Mrs Gregory decided to have her lower leg amputated in November last year, becoming one of 16 victims to lose a limb.

Living in Texas with her husband and son, she now works as a motivational speaker.

Orange is the New Black star Uzo Aduba, who plays Suzanne “Crazy Eyes” Warren, also ran the Boston Marathon, as did Sean Astin, who starred as Sam in the Lord of the Rings trilogy.

He was raising money for a charity honouring eight-year-old Martin Richard, the youngest victim of the bombings.

Dzhokhar Tsarnaev, the only surviving bomber, could be sentenced to death for his part in the attack after being convicted on 30 separate charges.

The 21-year-old ethnic Chechen killed three people and injured 264 at the marathon finish line and fatally shot a police officer as he and his older brother, Tamerlan, attempted to flee three days later.

Tamerlan, then 26, was killed in a shoot-out with police while the pair were on the run.

Additional reporting by Reuters