Brazil election: WhatsApp takes centre stage amid bitter campaign battle

Digital marketing firms had apparently taken advantage to circulate unregistered political propaganda

Facebook Inc's WhatsApp messaging service became the frontline in Brazil's bitter presidential campaign on Friday, as front-runner Jair Bolsonaro angrily denied accusations he had encouraged widespread misinformation campaigns on the platform.

On Thursday, newspaper Folha de S.Paulo had reported that supporters of the far-right candidate had funded mass messaging attacks against leftist rival Fernando Haddad.

Bolsonaro said in an online video that he had no knowledge of such activity and called on any supporters doing so to stop.

Haddad and his allies have urged an investigation and threatened a flurry of legal action, as the race that lawmaker Bolsonaro is