New Delhi, Nov. 9 -- A tornado struck the southern Brazilian state of Parana, killing six people and injuring more than 700 in what state officials call one of the most extreme weather events ever to hit the region.

After analysing the damage and weather conditions, the state's climate monitoring agency, Simepar, upgraded Friday's tornado from category F2 to F3. "In terms of magnitude, it was certainly the most devastating tornado we've ever had" in the state of Parana, Bloomberg quoted Simepar meteorologist Lizandro Jacobsen as saying.

Photos released by Parana's Civil Defense showed widespread destruction in the municipality of Rio Bonito do Iguacu, with homes, vehicles, and roads heavily damaged after the tornado. The state governmen...