At least 190 people in Malawi have died since Freddy smashed into southern Africa at the weekend, just weeks after it made a deadly hit in late February, according to Malawi government officials.
As heavy rains continued to pummel the country, 584 people have been injured and 37 are still missing, it said in a statement.
The commercial hub of Blantyre was the hardest hit district and severe flooding and rains have broken roads and bridges, hampering relief operations. Many have died in mudslides that have washed away makeshift homes there.
Families in Blantyre were counting the cost of the storm as they waited to collect the dead bodies of relatives from the Queen Elizabeth Central Hospital mortuary.
More than 19,000 people were affected by the storm in Malawi, according to the UN.
Despair settled on Chilobwe, a township on the city's outskirts that accounts for around half of the victims.
Drenched in rains that have been falling for days, survivors milled about in disbelief, looking at flattened houses and structures.
Many believed there were still people trapped underneath the muddy rubble of earthen bricks - but there were no rescuers in sight.
John Witman, in his 80s, in a raincoat and woolen hat, with his 10 family members in tow, stood in front of what was his son-in-law's house. There were just rocks left and gushing water, for the house had been washed away.
"I wish that we could find him, and find closure. We feel helpless because no one is here to help us - we don't know what to do," he told AFP.
In Chimkwankhunda, a district a few kilometers away, Steve Panganani Matera, wearing a high-visibility green jacket, pointed to a mound of mud.
"There were plenty of houses, but they are all gone," said Matera.
"There are plenty of bodies down there in the mud, plenty of bodies."
"People are trying to find a place to hang in there for some time."
The flooding and rains have hit rescue operations and made it difficult to get relief to those affected, aid agencies said.
"It's a challenging operation in the sense that there’s been incidents of mudslides and so people are getting stuck in those mud accumulations," said Estere Tsoka, emergency specialist at U.N. children's agency UNICEF in Malawi.
Relief workers also expected the toll to rise.
"The situation is very dire," said Guilherme Botelho, emergency project coordinator for Doctors Without Borders (MSF).
"There are many casualties, either wounded, missing or dead, and the numbers will only increase in the coming days."
- Deadly loop -
Cyclone Freddy reached landlocked Malawi early on Monday morning after sweeping through Mozambique at the weekend.
The storm last week unofficially broke the World Meteorological Organization's benchmark as the longest-lasting tropical cyclone on record, set in 1994 for a 31-day storm named John.
Confirming whether Freddy is the new titleholder is a process likely to take months.
Freddy brewed weeks ago off the north Australian coast, becoming a named storm on February 6.
It crossed the entire southern Indian Ocean and made landfall in Madagascar on February 21, traversing the island before reaching Mozambique on February 24 , claiming nearly two dozen lives in both countries and affecting nearly 400,000 people.
It then returned to the Indian Ocean, refueled on the warmth of its waters, and came back much more powerful at the weekend.
Meteorologists say that cyclones that track across the entire Indian Ocean are very infrequent - the last such occurrences were in 2000 - and Freddy's loopback is even more exceptional.
"It's a very rare thing that these cyclones feed themselves over and over again," said climate change expert and professor Coleen Vogel at South Africa's University of the Witwatersrand.
"People aren't expecting them to come back again once they've hit already."
"Climate change is starting to show impacts over these systems," Vogel said, adding however that more research was needed to say this with greater certainty.
The cyclone has piled more woes on a country grappling with the deadliest cholera outbreak in its history, which has killed over 1,600 people since last year.
Fears of a cholera resurgence after the outbreak started in the aftermath of another tropical storm, Anna last year, have been exacerbated by vaccines shortages.
"It's still early to tell if anything is going to happen, but we need to be vigilant to see if more cases will come, " said MSF's Botelho.
South Africa's President Cyril Ramaphosa expressed his condolences over the loss of nearly 150 lives in the three storm-hit countries.
This report was sourced from Reuters and Agence France-Presse.