WELLINGTON, New Zealand (AP) — A large fire that broke out Tuesday on the roof of a convention center that’s under construction in downtown Auckland sent plumes of thick black smoke over New Zealand’s largest city.

The St. John ambulance service said it took one person to Auckland City Hospital in a serious condition in the late afternoon, about three hours after the fire began. There were no initial reports of any deaths or other serious injuries from the blaze.

Authorities were asking people to stay away from the central city as more than 20 fire trucks rushed to the scene to help battle the blaze. Several roads were also closed.

The fire prompted SkyCity to evacuate its iconic downtown tower, as well as its hotels, casino and corporate offices that are located near the construction site.

The New Zealand International Convention Centre was scheduled to open next year and was expected to accommodate more than 3,000 people at conferences. Plans include a new 300-room hotel being built next to the center.

Work began on the site in 2015 and has been behind schedule and over budget. The project cost more than 700 million New Zealand dollars ($450 million).

Fire and Emergency spokesperson Dave Woon told media the fire was very difficult to extinguish.

“It is a large fire involving gas cylinders that started around the roof and guttering area and there is insulation on fire,” he said.