A participant in the Great North Run died at the event, according to race officials.
A spokesman for the organisers said: "The Great Run Company deeply regrets the loss of life of a participant at the Great North Run today and offer our deepest sympathies and condolences to the family and friends of the individual."
Tracey Cramond, who was running for the Butterwick Hospice in memory of her mother, was named as the millionth runner to take part in the event.
She said that as she crossed the finish line, "I heard a bang go off behind me...and then I got mobbed!"
Tracey was presented with a special award by Lord Coe.
A charity runner became the millionth person to finish the Great North Run in Newcastle.
Tracey Cramond crossed the line with a time of just over three hours and 22 minutes becoming the first millionth finisher ever in a running event worldwide.
She was in a mass of runners who surged through the line an hour and 22 minutes after race winner, the double Olympic gold medallist Mo Farah.
She told the BBC: "I'm absolutely gobsmacked - totally shocked," adding that she started running last year after her mother died.
She added: "I thought I would raise funds for children's charities because children meant so much to her."
Olympic champion Mo Farah has celebrated becoming the first British man to win the Great North Run since 1985 by beating Mike Kigen with a personal best time of one hour and one second.
Olympic, World and European champion Mo Farah made up for last year's heartbreak by winning the Great North Run in Newcastle.
The 31-year-old who lost in a sprint finish to Ethiopia's Kenenisa Bekele over the half-marathon course 12 months ago, scored a personal best time of 1:00:01.
Kenyan distance runner Mary Keitany has won the women's elite event at the Great North Run, with a finishing time of 65 minutes, 39 seconds.
Britain's Gemma Steel claimed second place.
Mo Farah tweeted to say he was "sorry" he didn't win the Great North Run after he was beaten by Ethiopia's Kenenisa Bekele in a sprint finish.