SANTO DOMINGO (Reuters) - Dominican Republic’s nationwide municipal elections were suspended only four hours after voting began on Sunday due to a glitch in the electronic voting system, officials said.

More than 7.4 million voters were due to vote to elect 3,849 positions in 158 municipalities across the Caribbean nation. The failure of the system is likely to raise concerns ahead of the May 17 presidential elections.

Julio Cesar Castanos, president of Dominican Republic’s electoral body, said nearly half of the electronic devices did not work properly and many virtual ballot papers did not load, leaving citizens unable to cast their votes.

“We are going to initiate a thorough investigation of what happened and why those ballot papers did not load correctly,” Castanos said in a press conference.

The electronic system was used in 18 of the 158 municipalities and focused on cities and regions with high population density, accounting for 62.4% of the electorate. Paper ballots were due to be used elsewhere.

Castanos said that the failures only occurred in the 18 municipalities that used electronic voting.

Eduardo Frei, president of the observer commission from the Organization of American States (OAS), recommended an exhaustive audit to determine the failure and called for a dialogue of all political sectors to find a solution and hold new elections.

Luis Abinader, leader of the opposition Modern Revolutionary Party, said the suspension of the vote was “outrageous and unjustified”.

Several opposition parties, such as the People’s Force, of former President Leonel Fernández, objected to the use of electronic voting due to fears software could be manipulated.