A fire that tore through a housing settlement in southern Chile Monday killed 14 Venezuelan migrants, including eight children, the deputy mayor of the city of Coronel said.

“We regret to announce the death of 14 residents of our community. There are three families, eight minors, and six adults who died as a result of this fire that destroyed their home,” Javier Valencia told journalists.

“These are Venezuelan families,” he said, adding that the fire’s cause was unknown but that investigators were looking into whether a heating unit overheated. Three families had crowded into the two homes destroyed by the fire, the deputy mayor said.

Valencia lamented the recent increase in the construction of housing on unauthorized land, known in Chile as “encampments,” where forest fires have become more common.

Coronel, a little south of Concepcion, Chile’s second most populous city, is one of the areas most affected by such fires, due to the high temperatures of the southern hemisphere summer.

Since 2017, Venezuelan migrant arrivals to Chile have increased exponentially. Thousands of migrants cross the border by walking from Bolivia or Peru through clandestine crossings.

According to official estimates, of the 1.7 million foreigners who arrived in Chile in recent years almost half are Venezuelans who fled the economic crisis in their country.