The main opposition candidate in Mali's contested elections said on Thursday he "categorically rejects" the results of the presidential run-off that handed a second term to Ibrahim Boubacar Keita.Former minister Soumaila Cisse, 68, who has slammed the August 12 run-off as marred by fraud, picked up 32.84% of the vote according to the official count, compared to 67.16% for Keita. "I categorically and unequivocally reject the results proclaimed by the Constitutional Court. Therefore, I do not recognise the president that it declared," Cisse said at a news conference in his first public reaction to the declaration of the final results on Monday. Keita, 73, who will begin his second five-year term on September 4, called for Cisse to accept the result.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook"It would be appropriate and desirable that here and now my young brother Soumaila Cisse takes the hand I extend to him and accept reality and not delusion," Keita said in Mauritania's capital Nouakchott, his first trip since his re-election."IBK did not forced the hand of Malians, did not stuff ballot boxes as it is said," he added, referring to himself by his initials, as his is universally known.He was re-elected despite fierce criticism of failures to tackle jihadist violence and ethnic tensions that have rocked the impoverished Sahel state.Cisse, whose supporters have gathered in their hundreds to protest the result in recent days, has claimed a wide range of electoral fraud was used in Keita's favour.But the Constitutional Court rejected his petition against the result as being inadmissible or unsupported by evidence. "This institution has discredited itself as a voluntary prisoner of an autocratic regime," Cisse said Thursday, calling for "peaceful" demonstrations in Bamako and other cities in Mali and beyond on Saturday.Observer missions sent by the European Union and the African Union (AU) have said the election was not badly impaired.