Seven people killed and extensive damage in urban areas was the result of hurricane strong winds and rain storms that struck Uruguay in the last 24 hours, reported officials in Montevideo.
The storm, which was described as the worst in recent years blew roofs; sunk yachts and fishing vessels in marinas; knocked energy pylons and trees, leaving vast areas without electricity and drinking water.
Two teenagers, 17 and 16, were killed in Montevideo when an antenna fell onto their house, and a 52-year-old woman was crushed by a tree in a nearby seaside resort.
In Maldonado, 80 miles east of Montevideo, a man was crushed by a tree, a homeless man died of hypothermia and a third person was electrocuted when trying to remove branches, reported the local police.
Maldonado authorities closed schools on Wednesday as a safety precaution until trees and other debris were removed from streets.
In Montevideo wind gusts recorded 160 kilometers (100 miles) per hour, causing havoc in street traffic, knocking over an estimated 2000 trees and the Fire Department received 3,600 emergency calls. The electricity company Wednesday midday had still over 12,000 services to reconnect. Highways Police reported that two national highways remained closed because of overflowing rivers and streams.
The storm also caused damage to the Uruguayan Congress building, which on Thursday is scheduled to celebrate its 80th anniversary with the presence of invited guests from several countries.
An exhibit of historical objects and furniture, including the country's first constitution, had to be taken down after a skylight broke and water cascaded into the hall where the items were displayed.
In neighbouring Argentina, the same storm system left at least two dead and forced the evacuation of 2,400 people in downtown Buenos Aires.
A 19-year-old woman and a 60-year-old man were crushed by walls that collapsed because of the rain in Lanus, a town on the outskirts of Buenos Aires.
Argentine Civil Defence authorities are working on a massive evacuation of people in the most-affected districts, including Avellaneda, Escobar, Lomas de Zamora and Pilar, all of which lowlands near the capital threatened by overflowing streams.