Parts of the venue for the COP30 climate summit in the Brazilian city of Belém were being evacuated following reports of a fire.
Brazil's tourism minister told reporters at the venue that the fire was under control and no one was hurt.
Minister for Climate Darragh O'Brien, who was at COP30, said that he was "evacuated quickly".
Speaking on RTÉ's Drivetime, he said: "Hopefully everyone is fine and there are no injuries."
"Emergency services are here at the scene. You can smell the burning, see the smoke. Everyone is evacuated out, very efficiently, without any panic in a very orderly way," he said.
The minister said he is not sure how the fire occurred at the event, which he said has 50,000 delegates attending each day.
Watch: George Lee reports live from Belém as COP30 evacuated due to fire
He added that it was a "substantial fire".
Security staff said the alert originated in the area of the venue where nations and organisations have their public-facing stands, known as pavilions.
Delegates, observers and journalists grabbed their bags and belongings and ran for the exits.
Police lined up as a barrier to prevent anyone from nearing the area, while a siren rang out in the background.
TV footage showed flames and smoke inside the venue, a conference center on the site of a former airport.
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