Mali's President Ibrahim Boubacar Keita has won Sunday's heavily disputed run-off election with 67.17% of the vote, official results show.

Opposition candidate Soumaila Cisse, who won 32.83% of the vote, said on Monday that he would reject the result as he believed the vote was marred by fraud.

"I call on all Malians to rise up... We will not accept the dictatorship of fraud," he said.

The internet could not be accessed via mobile phone networks in the capital, Bamako, ahead of the announcement of official results, AFP news agency reports.