Millions need aid in Yemen, whose government was ousted from the capital Sanaa by the Iran-allied Houthi group in 2014 before a Saudi-led military coalition then intervened in 2015 to try to restore President Abd-Rabbu Mansour Hadi.

State-run Saudi Press Agency on Friday cited a directive from King Salman confirming Tuesday’s donor conference in Riyadh where the United Nations aspires to raise $2.4 billion for the world’s biggest aid operation.

“If we don’t get the funding we need and if more isn’t done to suppress the virus, COVID-19 could engulf Yemen,” said Lise Grande, the U.N. Humanitarian Coordinator for Yemen, in a statement.

Yemen reported as of Thursday 281 infections and 55 deaths, amounting to a fatality rate of 20%, compared to a global average estimated by the United Nations at 7%.