The death toll from an explosion that hit a commercial area of a town in the Dominican Republic has risen to 27, authorities said Wednesday.

The blast on Monday sent shock waves through the commercial area of San Cristobal, less than 30 kilometers (18 miles) from the capital Santo Domingo, sparking a fire that is still partially burning two days later.

Juan Manuel Mendez, the director of the country's emergency operations center, gave the updated figures at a news conference, saying the priority now was on extinguishing the fire.

Civil defense official Delfin Antonio Rodriguez told local news channel SIN that 90% of the blaze had been extinguished.

Of the 59 people injured, 37 remained hospitalized, officials said.

Local media reported that some of the wounded had suffered burns on up to 40% of their bodies.

"This is an event which has affected us all, we are all very shocked, very sad," said President Luis Abinader, who attended a mass in honor of the victims.

He declared Thursday a day of national mourning, during which flags will fly at half-mast.

Authorities confirmed on Monday that a four-month-old baby was among the dead.

The cause of the explosion has not been determined, nor has its exact origin.

The blast and resulting fire affected nine buildings and partially destroyed four.

Some 500 firefighters and other rescue officials were sent to the scene, with search dogs used to comb the debris.