The memo, which was sent to AFP by two independent sources and the content of which was confirmed by a third source, said that UNHCR was "facing a period of financial uncertainty, owing primarily (but not only) to the continued freeze on all foreign aid decided by the United States – historically our biggest donor".
Humanitarian organisations worldwide have been reeling since Donald Trump's return as president in January, pushing an anti-refugee and anti-migrant agenda and immediately freezing most US foreign aid funding.
The UN refugee agency, which had relied on the United States to cover over 40% of its budget, already told AFP last month that it planned to cut "some 600 staff positions" out of a global workforce of nearly 20,000.
It was unclear how many more jobs would go, a senior UNHCR staff member said on condition of anonymity.
"The morale of people is very low...There are a lot of rumours; maybe 30% of the staff will be cut. Maybe more," the senior staff member said.
"As of today, there is no clear information, and that is also a source of frustration."
The staff member said there was significant frustration inside UNHCR over the fact that management had allowed so much of the agency's budget to be covered by a single donor.
"This situation would not have happened if a more balanced approach to funding would have been taken."
UNHCR is not the only organisation that has been hit. The UN's International Organization for Migration for instance said this week that it was laying off 6,000 of its staff.
In his public statement, Grandi focused first and foremost on the dire consequences cuts were already having on some of the world's most vulnerable people.
"With less funding, fewer staff and a smaller UNHCR presence in countries hosting refugees, the equation is simple: lives will be lost," he cautioned.
"Refugee women and girls at extreme risk of rape and other abuse are already losing access to services that kept them safe," he said.
"Children are being left without teachers or schools, pushing them into child labour, trafficking or early marriage. Refugee communities will have less shelter, water and food."
Grandi insisted that "this is not just a funding shortfall" but "a crisis of responsibility".
"We appeal to member states to honour their commitments to displaced people."
