A hydroelectric dam has collapsed in southern Brazil after days of heavy rains that triggered massive flooding, killing more than 30 people.

Officials say another 60 people are missing in Rio Grande do Sul state.

About 15,000 residents have fled their homes since Saturday. At least 500,000 people are without power and clean water across the state.

The burst dam triggered a two-metre (6.6ft) wave, causing panic and further damage in the already flooded areas.

The dam is located between the municipality of Cotiporã and the city of Bento Gonçalves.

The death toll keeps climbing from continuous rains in Brazil's southern state of Rio Grande do Sul. At least 58 people have been killed, while another 67 remain missing according to the state's civil defense agency. The rains have triggered the worst floods in more than 80 years.

Rescuers rushed to evacuate people stranded by devastating floods across the southern Brazilian state of Rio Grande do Sul on Tuesday, with 90 reported dead and desperate survivors seeking food and basic supplies.

On the outskirts of Eldorado do Sul, 17 kilometers (10.5 miles) from the state capital of Porto Alegre, many people who left their homes were sleeping on the roadside and told Reuters they were going hungry. Entire families were leaving on foot, carrying belongings in backpacks and shopping carts.

"We've been without food for three days and we've only just got this blanket. I'm with people I don't even know, I don't know where my family is," said a young man who gave his name as Ricardo Junior.

The flooding has hampered rescue efforts, with dozens of people still waiting to be evacuated by boat or helicopter from stricken homes. Small boats crisscrossed the flooded town searching for survivors.

The state's Civil Defense agency said the death toll has risen to 90 with another four deaths being investigated, while 131 people are still unaccounted for and 155,000 are homeless.

Heavy rains that began last week have caused rivers to flood, inundating whole towns and destroying roads and bridges.

In Porto Alegre, a city of 1.3 million inhabitants on the Guaiba river, downtown streets were under water.

Porto Alegre residents faced empty supermarket shelves and closed gas stations, with shops rationing sales of mineral water. The city distributed water in trucks to hospitals and shelters.

The floods have also impacted water and electricity services, with more than 1.4 million affected overall, according to Brazil's Civil Defense.

The death toll from floods caused by heavy rains in Brazil has risen to 137, authorities reported Saturday.

Following heavy rains that have been affecting the southern state of Rio Grande do Sul since last week, the loss of life and property is steadily increasing.

According to a statement from the Civil Defense of the state, the number is 125 people still missing.

The number of injured has risen to 756, and more than 2 million people have been affected.

Additionally, the statement noted that more tha 600,000 people have been displaced.

The statement highlighted that hospitals have reached full capacity, necessitating additional support for patient care.

The death toll from devastating flash floods in northern Afghanistan has risen to 153 people across three provinces, the Taliban's interior ministry said on Saturday.

At least 138 people have also been injured in the flooding across northern Baghlan, Takhar and Badakhshan, caused by heavy rains on Friday, ministry spokesman Abdul Mateen Qaniee told Reuters.

Taliban authorities sent helicopters to try to assist civilians overnight after receiving reports that over 100 people were stranded.

Many people had been left homeless and transportation, water and waste systems were "severely disrupted", according to the World Health Organisation (WHO).

"The impact has been profound, leading to loss of life and injuries, with many individuals still unaccounted for," the WHO's Afghanistan office said in a statement late on Friday.

It added that four health centres had been damaged and one destroyed by the floods and said the agency was sending health teams to provide treatment in the inundated areas.

Flash floods caused by heavy rains have devastated villages in northern Afghanistan, killing 315 people and injuring more than 1,600, authorities said on Sunday, as villagers buried their dead and aid agencies warned of widening havoc.

Thousands of homes were damaged and livestock wiped out, the Taliban-run refugee ministry said, while aid groups warned of damage to health care facilities and vital infrastructure, such as water supply, with streets left coated in mud.

In the Nahrin district of Baghlan province, people carried their shrouded dead to a gravesite.

"We have no food, no drinking water, no shelter, no blankets, nothing at all, floods have destroyed everything," said Muhammad Yahqoob, who has lost 13 members of his family, children among them.

The survivors were struggling to cope, he added.

"Out of 42 houses, only two or three remain, it has destroyed the entire valley."