Senegal's prime minister claims that incumbent president Macky Sall has won re-election, though the opposition rejects the assertion and says the vote should go to a runoff.

Prime Minister Mahammed Boun Abdallah Dionne, who is from the ruling party, told reporters late Sunday that his unofficial results show that Sall had won 57 percent of the vote. The winning candidate must get more than 50 percent of the vote to avoid a second round.

However, the top opposition candidate Idrissa Seck told reporters that he and his supporters do not accept the unofficial reports of a Sall victory.

Senegal's electoral commission will release the official results, and that is not expected until Tuesday.

Sall faced four challengers in Sunday's vote including Seck, who has run for the office twice before.