SANTO DOMINGO, Dominican Republic (AFP) — The Dominican Republic said Wednesday that power had been restored to almost all of the national grid following a massive blackout that sparked protests in two cities.

A failure in the transmission lines on Tuesday left much of the Caribbean country in darkness, including the capital Santo Domingo and Punta Cana, a tourist magnet.

All power generation plants were now operational, and the electrical transmission system was operating at 100 per cent, allowing them to meet 96 per cent of national demand, Energy Minister Joel Santos Echavarria said in a statement.

The outage caused chaotic traffic jams. Metro service in Santo Domingo was also suspended for hours, with riders having to be evacuated.

Throughout the night, local media and social media users reported street protests with tyre burning due to the lack of electricity in the neighbourhoods of Santiago and San Pedro de Macorís. The CDN channel also reported the arrest of several people.

The ministry announced an investigation into the outage.

“We cannot clearly speak of sabotage” until an investigation is complete, the energy minister said.

Power outages are frequent in the Dominican Republic, where citizens report cuts lasting up to 10 hours. Lack of maintenance, breakdowns and illegal connections are among the causes.