Serbian President Aleksandar Vucic stepped down as leader of the ruling Serbian Progressive Party (SNS) at a party congress on Saturday, saying a new approach was needed to unite the country, but said he would remain head of state.
Another anti-government protest is scheduled for later on Saturday.
Leaders of the SNS accepted Vucic's resignation offer at the party congress in Kragujevac, central Serbia, and appointed defense minister Milos Vucevic to replace him, as Vucic had proposed.
Opposition parties and rights watchdogs have long accused Vucic and the SNS of autocracy, stifling media freedoms, violence against political opponents, corruption and ties with organized crime.
Vucic and his allies deny the accusations.