Catholic aid agency CAFOD says it has been left shocked as the scale of the destruction caused by Cyclone Idai across southern Africa becomes more apparent.
It has partnered with the Disasters Emergency Committee to assist hundreds of thousands of people affected by the storm, which is believed to have killed at least 1,000 people in Mozambique alone.
Tens of thousands have been left homeless after the cyclone battered Beira city, in Mozambique's Sofala Province, where winds reached up to 140km/h and torrential rains submerged nearly 90 per cent of the city.
Although Mozambique is believed to be the worst affected country, huge devastation has been wrought across Zimbabwe and Malawi, where hundreds more have died.
CAFOD estimates that 2.6 million people across the two countries are in need of humanitarian aid to see them through the coming weeks.
In a Twitter update, the aid agency said things were "getting worse" for the countries affected.
"Despite the cyclone hitting over a week ago, we fear that the disaster is getting worse," it said.
CAFOD's Director, Christine Allen, said: "The more we see and hear of the destruction caused by Cyclone Idai, the more shocking is the devastating impact on the lives of children, women and men. Reports from the ground tell us of entire villages submerged and whole families missing.
"But there are still lives to be saved and communities who need our help. We cannot waste any time reaching those in urgent need.
"We've already seen how the Catholic community has responded, here in England and Wales and through our global church network. CAFOD has made an initial £100,000 pledge for Mozambique and £50,000 for Zimbabwe, but much more will be needed as the disaster unfolds.
"This money will help families who have lost everything to survive the coming days. Knowing they are not alone will give them hope."
Communities are also suffering after Idai wiped out crops and washed away homes, roads and bridges.
In addition to food shortages, the extensive flood waters have given rise to fears of water-borne diseases and sanitation issues.
Gabriel Bertani, CAFOD's Country Representative for Mozambique, said: "Powerful cyclones like Idai damage water supplies and sanitation facilities which increases the risk of water-borne diseases spreading.
"In the low-lying areas, flood waters have caused widespread damage to crops and livestock, leaving people with very limited food for their daily needs."
CAFOD is working with local Caritas emergency response experts to help provide shelter and distribute emergency food, including rice, beans, sugar and cooking oil, as well as hygiene kits.
Bishop Charles Kasonde of Solwezi, who also chairs the Association of Episcopal Conferences in Eastern Africa, has asked for prayers for all those involved in rescue operations and providing humanitarian assistance.
"I also pray that our partners and people of good will who have always journeyed with us in both good and bad times may rise up to the call," he said.
Christian aid agency Tearfund is also working with local partners to provide food, shelter and cooking utensils to people affected by Idai, and has released £53,000 for relief efforts across the three affected countries.
With the cyclone damaging crops that were ready for harvesting, Tearfund is planning to distribute seeds to mitigate the impact of the expected food shortages.
Tearfund's Country Director in Mozambique, Edgar Jone, explained: "This is a catastrophe. It's a huge setback for the work we are doing to support people to overcome poverty in Mozambique.
"Our priority now is to reach those people who have lost so much and support them to get back on their feet.
"Cyclone Idai has destroyed so much in an instance, and it will take years for people to recover what they have lost."
Earnest Maswera, Tearfund's Country Director in Zimbabwe, said it was the "worst possible time" for the cyclone to strike as crops had been just weeks away from harvesting.
"The loss of crops aggravates existing challenges we have been facing because even before the floods 5.3 million people had been experiencing food shortages and this will increase significantly," he said.
In addition to claiming dozens of lives, he said that the cyclone had caused "immeasurable" destruction to houses, farms and infrastructure in Zimbabwe, with the damage to roads and bridges making many areas inaccessible.
Tearfund is working with its partner, the Evangelical Fellowship of Zimbabwe, to bring clean water, sanitation solutions, and trauma counselling to those affected in Buhera district.
At least 300 households will receive food, blankets and utensils from the aid agency.
In Malawi, where at least 56 people have been killed, Tearfund's country director Vincent Moyo said flooding was a major issue.
He estimates that over 22,000 homes have been destroyed, displacing 110,000 people.
"Currently we need plastic tarpaulins for shelter, food and clean treated water that is safe to drink. We are also aiming to prevent water borne diseases that may arise as a result of the floods," he said.
To donate to Tearfund's Disaster Relief Fund, visit https://www.tearfund.org/give/when_disaster_strikes/
To donate to CAFOD's Cyclone Idai Appeal, visit https://cafod.org.uk/donations/