Opposition candidate Soumaila Cisse on Friday called on parties to forge a "broad democratic front" for a run-off presidential election on August 12 against incumbent Ibrahim Boubacar Keita.Speaking to hundreds of supporters outside his party headquarters, Cisse slammed an official tally of Sunday's first round results which gave him just 17.8% of votes to 41.42% for Keita, as "neither sincere, nor credible" and "a fraud".Violence disrupted polling in several areas beset by ethnic and jihadist unrest despite the deployment of 30 000 security personnel for the vote and Cisse said the official outcome was a travesty as he urged beaten rivals to swing behind him."These are the results of fraud, a shameful vote rigging in favour of the outgoing president," railed Cisse. "We will not accept it", the former finance minister vowed.He urged the 22 candidates eliminated in the first round to support him and create a "broad democratic front against fraud and for political change," adding he believed that a majority of people backed change.Cisse, 68, also stood against Keita in 2013 but ended up well beaten.This time, he insisted, victory was "within reach" if anti-Keita forces stood together. The only female candidate, Djeneba N'Diaye, said earlier that her 11 600-strong support, equivalent to a 0.36% vote share, would now plump for Keita.Teams from the European Union, the African Union, the regional Ecowas grouping and the Francophonie organisation sent observers to Sunday's poll with the international community hoping the winner can foster broad support for strengthening a 2015 peace accord. The government and mainly Touareg former rebels signed the agreement but its actual application has remained out of reach as jihadist violence has continued amid repeated states of emergency, the unrest permeating neighbouring Burkina Faso and Niger.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook.