The second round of the Haiti's presidential election scheduled for Sunday has been postponed again amid violent protests in the country.

Pierre-Louis Opont, chairman of the Electoral Council, said Friday that the vote has been cancelled due to "security concerns," according to BBC News. The second round of the election was first scheduled on Dec. 27.

Opposition candidate Jude Celestin, who secured 25.29 percent vote over President Michel Martelly's hand-picked successor Jovenel Moise' 32.76 percent in the first round of vote in Novemeber, vowed to boycott the run-off.

"On the 24th, it's 'No'. I won't take part in this farce, it will be a selection not an election because there will only be one candidate," Celestin said in an interview with AFP earlier this week, France24 reported.

President Martelly, who is constitutionally barred from seeking re-election, remained defiant. "They want to take power their way, because they can't take it through the ballot," Martelly said Thursday, according to DW.

The United Nations reiterated its support for an inclusive and fair electoral process.

Sandra Honoré, Special Representative of the Secretary-General in Haiti, said that the U.N. and its partners maintained their "full support to the efforts aimed at identifying consensual and constructive solutions to the current challenges of governance of Haiti through elections and dialogue between stakeholders," according to the UN News Center.