Rwandans have voted overwhelmingly to allow President Paul Kagame to extend his term in office.
Roch Marc Christian Kabore secured presidency outright after months of political unrest.
Similar attempts to extend power have provoked violence in Burundi and the Republic of Congo.
President Barack Obama praised country's commitment to democracy since the end of the 2003 civil war.
Tanzania's governing CCM party candidate John Magufuli won the election with 58% of the vote.
Voters in Congo Republic have overwhelmingly backed a change in the constitution.
Incumbent won second term, election commission announced, six days after polling ended.
Former President Mathieu Kerekou hailed as helping to usher in multi-party democracy in Africa.
Voters electing leader in country's second democratic presidential election since independence in 1958.
Burundi has expelled a Rwandan diplomat, whom it accuses of destabilizing the country.