Olympic athlete Rebecca Cheptegei has died days after being doused in petrol and set on fire by former boyfriend, Ugandan official says.

The 33-year-old Ugandan marathon runner, who competed in Paris, had suffered extensive burns after Sunday's attack, the doctor treating her had said.

The authorities in north-west Kenya, where Cheptegei lived and trained, said she was targeted after returning home from church.

A report filed by a local administrator alleged the athlete and her ex-partner had been wrangling over a piece of land. Police say an investigation is under way.