Opponents of Serbian President Aleksandar Vučić gathered on Friday evening outside the Constitutional Court building demanding last month’s elections be annulled due to widespread irregularities reported by both local and international observers.

The group “Serbia Against Violence” accused President Vučić’s Government of orchestrating fraud in the parliamentary and local elections on December 17, particularly in Belgrade, the Serbian capital. President Vučić has denied the allegations.

The State Electoral Commission declared Vučić’s Progressive Party the winner of the elections and dismissed opposition appeals. The Constitutional Court has yet to rule on the appeals.

Opposition politician Radomir Lazović said, “This is a battle for everyone because everyone loses with this (electoral abuse)”.

Around 2,000 protesters also marched towards the headquarters of Serbia’s public broadcaster RTS, which they accuse of being pro-government.

International election observers reported cases of vote-buying and ballot box stuffing, stating that Serbian elections were held under “unfair conditions” overall.

Opposition parties and independent local observers claimed that voters were bused into Belgrade to cast ballots for the ruling party after being registered at false addresses.

Thousands protested for days at the end of December, accusing President Vučić of election theft. Police used tear gas and arrested dozens as protesters attempted to enter the Belgrade city hall during one of the demonstrations.

While President Vučić says he wants to lead Serbia towards European Union membership, critics accuse the populist leader of imposing autocracy by taking control of major media outlets and key state institutions.

Serbia needs to strengthen the rule of law and democratic freedoms to become a member of the bloc of 27 countries.