The devastating wildfires tearing across large parts of Chile are believed to be the country’s deadliest on record, according to the United Nations disaster agency, as firefighters struggle to contain more than 160 blazes after days of burning.

The fires have claimed at least 123 lives and hundreds of people are still missing, according to Chilean authorities. Officials also said that 33 bodies have been identified and 79 autopsies have been conducted.

Chile’s wildfires come as countries across South America, including Argentina, Colombia, and Paraguay, have experienced scorching heat waves, as the impacts of El Niño, a natural climate fluctuation with a global heating impact, collides with a long-term trend of global warming.

The fires have devastated swaths of central and northern Chile, destroying thousands of homes and buildings. President Gabriel Boric declared a state of emergency Sunday as coastal cities including Viña del Mar and Valparaiso choked with smoke.

He declared Monday and Tuesday as days of national mourning for fire victims.

More than 560 tons of aid have been delivered to affected communities, SENAPRED said.