Two 25-year-old runners have died during the Great North Run. Both runners suddenly collapsed during the race.

Race organizers say 63,000 runners took part in the Great North Run.

According to organizers, both runners were from northeast England and were participating in the 13.1-mile half-marathon.

The race organizers say that despite the best efforts of the medical teams, the two runners could not survive, the cause of death is still unknown.

Keep in mind that the Great North Run is considered the world’s largest half marathon. This year saw the 45th edition of the Great North Run from Newcastle to South Shields.