MILAN (AP) — A guard at a construction site near a 2026 Winter Olympic venue in the mountain resort of Cortina d’Ampezzo died during a frigid overnight shift, authorities confirmed on Saturday.

Italy’s Infrastructure Minister Matteo Salvini called for a full investigation into the circumstances of the 55-year-old worker’s death.

Italian media reported that the death occurred on Thursday while the worker was on duty at a construction site near Cortina’s ice arena. Temperatures that night plunged to minus 12 degrees Celsius (10.4 degrees Fahrenheit.)

Milan Cortina organizers said that the worker died of a heart attack.

“The information we have is that it was a death by natural cause, it was a heart attack. And we are investigating,” Andrea Varnier, CEO of the Fondazione Milano Cortina 2026, told reporters at a test event at the new hockey arena in Milan.

“All the documentation that we have was in order. And we are waiting for the investigation to understand what the specific cause was. At the moment, the information we have from the emergency services is it was a death caused by natural causes … while he was on site,” Varnier said.

The Milan Cortina Winter Olympics are scheduled for Feb. 6-22.

The construction site was not one overseen by Simico, the governmental company responsible for Olympic infrastructure, the company said in a statement expressing its condolences.

Cortina city officials said they were “deeply saddened and troubled by the death.’’

Cortina will host curling, sliding and women’s Alpine skiing.