"The landslide buried more than 2,000 people alive and caused major destruction to buildings, food gardens, and caused major impact on the economic lifeline of the country," Mana wrote.
"This situation necessitates immediate action and international support to mitigate further losses and provide essential aid to those affected."
The landslide buried the village of Yambali in Enga Province beneath 20-26 feet of earth, according to U.N. News. It took place at around 3:00 am local time on Friday, May 24.
"It has occurred when people were still asleep in the early hours and the entire village has gone down," Elizabeth Laruma, the president of the Porgera Women in Business Association, told the Australian Broadcasting Corporation (ABC).
Laruma said the entire face of the mountain collapsed, squashing homes. Images showed rescue workers moving around downed trees and boulders. Some of the stones unleashed were larger than shipping containers.
"I have 18 of my family members being buried under the debris and soil that I am standing on, and a lot more family members in the village I cannot count," resident Evit Kambu told Reuters. "But I cannot retrieve the bodies, so I am standing here helplessly."
Initial reports put the death toll at around 100. Then, on Sunday, Serhan Aktoprak, country head of the U.N.'s International Organization for Migration (IOM), said that approximately 670 people were thought to be buried under the debris and that "hopes of finding them alive are shrinking."
It is not clear how the government reached its figure of more than 2,000 dead, and IOM has not altered its figures.
"We are not able to dispute what the government suggests but we are not able to comment on it," Aktoprak told AP, adding, "As time goes in such a massive undertaking, the number will remain fluid."
The landslide covered 150 homes and displaced around 1,250 people, according to IOM. It also blocked off the only highway traveling into the affected province, making rescue operations more difficult. So far, only five bodies have been pulled from the debris, according to AP. Rescue workers and survivors had been attempting to dig people out of the earth with shovels and farm equipment until the first excavator was donated by a local construction business on Sunday.
In the letter to the U.N., Mana said the ground was still shifting, making the situation "unstable" and posing "ongoing danger to both the rescue teams and survivors alike."
There have also been challenges delivering aid to the survivors: a Saturday delivery brought tarps and water but no food, while the local government gathered food and water on Sunday for only 600 people, The New York Times reported.
"This situation necessitates immediate action and international support to mitigate further losses and provide essential aid to those affected," IOM spokesperson Anne Mandal told the Times.
"If you increase that intensity, you're taking the landscape into an environment it's never experienced, and it will respond. And a landslide is the inevitable response."
International leaders have expressed support.
"Jill and I are heartbroken by the loss of life and devastation caused by the landslide in Papua New Guinea," U.S. President Joe Biden said in a statement. "Our prayers are with all the families impacted by this tragedy and all the first responders who are putting themselves in harm's way to help their fellow citizens."
Australia's Foreign Minister Penny Wong pledged her country's support, saying Friday: "The loss of life and destruction is devastating. As friends and partners, Australia stands ready to assist in relief and recovery efforts."
U.N. Secretary-General António Guterres offered "deep solidarity to the people and the government of Papua New Guinea" and "condolences to the victims of the devastating landslides that have caused horrific death and destruction."
The cause of Friday's landslide is under investigation, according toThe Washington Post, but some people in the area have attributed it to a lightning strike or a month of heavy rainfall. The mountain was also already unstable because of a previous landslide, according to U.S. Geological Survey geologist Kate Allstadt.
Papua New Guinea is often struck by fatal landslides, according to ABC. Partly this is because it is a mountainous, tropical country on the Ring of Fire, where both heavy rainstorms and seismic events can destabilize hillsides. It also has a poor, rural population who are more likely to live in a landslide's path.
However, human activities also increase the risk, with industries such as mining, logging, and liquefied natural gas destabilizing terrain or contributing to deforestation. The climate crisis also makes extreme weather events that trigger landslides more likely.
"Slopes are particularly sensitive to short-duration, high-intensity rainfall events," University of Hull vice-chancellor Dave Petley told ABC. "You can go back to first principles—imagine a landscape evolves to deal with the most intense rainfall it experiences. If you increase that intensity, you're taking the landscape into an environment it's never experienced, and it will respond. And a landslide is the inevitable response."
Stand.Earth international program director and chair of the Fossil Fuel Non-Proliferation Treaty Tzeporah Berman spoke out in response to Friday's landslide, as well as a heatwave in India and Pakistan and a cyclone in Bangladesh.
"Every ton of new oil, gas, and coal projects will cost lives," she wrote. "It's time for a fossil treaty."