The United Nations on Friday expressed deep concern over a deadly drone and missile attack in Yemen that came close to humanitarian workers’ housing.

“The United Nations is deeply concerned by Thursday’s missile and drone attack in Marib City, which reportedly caused dozens of civilian casualties,” said the UN Office for the Coordination of Humanitarian Affairs (OCHA). “It also occurred close to the compounds in Marib City where humanitarian workers are housed.”

Following an attack over the weekend on a Marib City fuel station, the latest incident reinforces yet again how civilians in Yemen are bearing the brunt in this conflict, the humanitarian office said.

“The United Nations urges the parties to the conflict to uphold their obligations under international humanitarian law, including ensuring the protection of civilians, aid workers and civilian infrastructure,” OCHA said.

Six years of conflict in Yemen has created the world’s largest humanitarian crisis, the office said. More than 20 million people — two-thirds of the population — rely on humanitarian assistance, and the country is at risk of slipping into famine, OCHA said. “What Yemenis need right now is peace — not further escalations to their suffering.”

The Yemen humanitarian response plan is currently 43 percent funded, with 1.65 billion U.S. dollars received out of the 3.85 billion U.S. dollars required.