(Corrects third paragraph to show was unclear who fired the guns; removes reference to pistols in second paragraph)
* Rumour sparks riot in Guinea's second city
* Flare-up in Ebola cases reported in southern border region
CONAKRY, Aug 29 (Reuters) - Riots broke out in Guinea's second-largest city Nzerekore over rumours that health workers had infected people with the deadly Ebola virus, a Red Cross official and residents said on Friday.
A crowd of young men, some armed with clubs and knives, set up barricades across the southern city on Thursday and threatened to attack the hospital before security forces moved in to restore order.
Gunshots were fired and several people were injured, said Youssouf Traore, president of the Guinean Red Cross.
"A rumour, which was totally false, spread that we had sprayed the market in order to transmit the virus to locals," Traore said. "People revolted and resorted to violence, prompting soldiers to intervene."
Local Red Cross workers had to flee to the military camp with their medical equipment.
Another resident said the security forces were preventing people leaving their neighbourhoods overnight.
The highly contagious Ebola virus was first reported in southeastern Guinea in March and to date has killed more than 1,500 people in the worst outbreak in history.
More than 400 people have died in Guinea, although the rate of infection is slower than in neighbouring Liberia and Sierra Leone.
Conakry says it has controlled the epidemic but has expressed concern over rising cases in the southern border region, which it blames on victims spilling over from neighbouring countries in search of better treatment.
The Guinean government's last health report for 26 August showed there were 12 suspected, probable and confirmed Ebola cases in Nzerekore. (Reporting by Saliou Samb; Writing by Emma Farge; Editing by Angus MacSwan)