The head of Burundi's electoral commission says vote counting is underway and results are expected Thursday for a controversial election in which incumbent President Pierre Nkurunziza's bid for a third term in power has sparked widespread unrest.

Electoral Commission President Pierre-Claver Ndayicariye said Wednesday that 74 percent of the 3.8 million registered voters cast their ballots. Nkurunziza is expected to win the election after some opposition groups boycotted the poll.

The U.S. said the legitimacy of the election has been tainted by the government's harassment of opposition and civic groups, closing down of media outlets and intimidation of voters. More than 100 people have died in protests opposing Nkurunziza's bid for a third term that opponents say is unconstitutional.