“Hundreds of policemen came and surrounded the headquarters, then came in and beat us and fired tear gas,” said Alou Niang, a protester.
Several people were taken to hospital amid the clashes.
“There were 16 injured evacuated to hospital, 10 of them have already been released. One policeman was injured,” said Amadou Sangho, spokesman for the Ministry of Security, adding a police vehicle was damaged and eight people were arrested.
“I was lightly injured participating in the march calling for credible elections. Thank God I was able to help some of the wounded women and young people,” Mamadou Igor Diarra, an opposition presidential candidate, wrote on his Twitter account.
Around a dozen candidates have announced their candidacy, the strongest of which is seen as opposition leader Soumaila Cisse, a former finance minister.