At least 10 people have been gored to death during bull runs in Spain this summer, with commentators blaming the "abnormal" number of fatalities on social media.

Four more deaths were recorded over the past weekend, including an 18-year-old man and a 33-year-old Spanish politician, The Guardian reports .

José Alberto Peñas López, a Socialist councillor from Traspinedo, north of Madrid, was closely following a bull as it dashed through the final stages of the run when suddenly the animal turned back and charged repeatedly at him.

The 18-year-old man died after being gored in the abdomen, while a 53-year-old spectator was gored six times in Blanca, near Murcia.

"This number isn't normal," said Antonio Lorca, a bullfighting critic for Spanish newspaper El País.

All the deaths happened during bull runs, not in bullfights, with Spain's recent economic crisis forcing around 300 fewer bullfights in 2015 compared to previous years.

Jesus Hijosa, mayor of Villaseca de la Sagra, a town 60km south of Madrid, blames the death of a 32-year-old man who was gored last week on his desperation for social media fame.

"The young man was in the path of a bull run which he was filming with his mobile phone," Mr Hijosa told Agence France-Presse.

"A bull surprised him from behind and gored him in the neck."