A desperate search was underway Friday for people buried by a deluge of mud that swept through the Brazilian city of Petropolis, leaving what President Jair Bolsonaro described as "scenes of war." 

A total of 136 bodies have been retrieved to date, according to civil defense officials, in the normally scenic tourist town some 60 kilometers (37 miles) north of Rio de Janeiro.  

But after three days, hopes of finding more survivors were fading fast. Petropolis mayor Rubens Bomtempo told a press conference late Friday that "it is difficult after so much time" to find anyone alive. 

On Tuesday, the streets of the city were turned into torrential rivers of mud that swept away homes, cars and trees following the heaviest rains to hit the region since 1932, Rio governor Claudio Castro said. 

"We saw enormous destruction, like scenes of war," Bolsonaro told reporters after his helicopter flyover Friday. 

He had headed straight for Petropolis on his return to Brazil after an official visit to Russia and Hungary.   

Officials said late Friday that 218 people were still missing, some of whom are likely to be among the 57 bodies that are still unidentified, according to authorities.  

On Friday morning, the alarm bells rang once again in areas at high risk of landslides in the city of 300,000 people.   

"There is a risk of landslides... be careful, move to a safe place," came the message over loudhailers amid renewed heavy rain in the early morning, which later subsided.   

"Everyone is very frightened and jumps at the slightest noise," said Atenor Alves de Alcantara, a 67-year-old retiree whose home was in the path of the water.  

"It is good that the President is visiting us, but it won't change anything," he added.   

- Sense of abandonment -

More than 500 firefighters with helicopters, excavation machinery and sniffer dogs continued the search, even as hope dwindled of finding anyone alive.  

Hundreds of volunteers were lending a hand to residents digging through the mud themselves in a frantic search for missing loved ones.  

In the Alta de Serra neighborhood, 80 houses were engulfed, and the bodies of 98 people have been recovered since Tuesday.  

"There could still be 50 people under there," said Roberto Amaral, coordinator of the fire brigade's special rescue group.

"We would like to finish the search as soon as possible, but we will work until the last body is removed," he added.    

Many inhabitants said they felt abandoned. 

Bolsonaro said people had the right to criticize, but "we cannot predict everything that will happen in 8.5 million square kilometers" (3.3 million square miles) -- the surface area of Brazil.  

"This is not the first time a tragedy has happened here," said the president, adding that "we will do our part."  

Petropolis and the surrounding region were previously hit by severe storms in January 2011, when more than 900 people died in flooding and landslides.  

Tuesday's was the latest in a series of deadly storms -- which experts say are made worse by climate change -- to hit Brazil in the past three months.  

Last month, torrential downpours triggered floods and landslides that killed at least 28 people in southeastern Brazil, mainly in Sao Paulo state. 

There have also been heavy rains in the northeastern state of Bahia, where 24 people died in December.  

Pope Francis sent a message of condolences Friday, and assured the community in a statement from the Vatican of his "participation in the grief of all those who are bereaved or who have been deprived of their possessions."