More than 1,000 people evacuated homes in the area, officials said.

Local media said two sisters, aged four and one, remained missing.

"The national and provincial governments are collaborating to deal with the storm," Buenos Aires government minister Carlos Bianco told local radio station Futurock.

"Basically, we have to rebuild a city. There are people who lost everything."

The Bahia Blanca mayor's office put the number of dead at 10, adding that at least five people died in flooded roadways.

The death toll in the city of 350,000 could still rise, the office said.

It put the number of evacuees at 1,128 as of early Saturday.

The downpour, which began Friday morning, was "unprecedented," dumping more than 15 inches (400 millimeters) of rain in the area in just eight hours, according to the province's security minister, Javier Alonso.

- Desolation -

Local media showed images of flooded shops and reported overnight looting.

The government has authorized emergency reconstruction aid of 10 billion pesos ($9.2 million at the official exchange rate).

The storm left much of the surrounding coastal area without power, though the local electric utility had restored service to some 30,000 users by Saturday morning.

Bahia Blanca has suffered past weather-related disasters, including a storm in December 2023 that claimed 13 lives.

In the resort town of Mar del Plata, south of Bahia Blanca, officials suspended evening activities Friday and urged people to remain indoors.

The city of Buenos Aires was also hit by the storm but suffered no major damage.