NEWS BRIEF The United Nations said Tuesday at least 10,000 civilians have been killed during Yemen’s 18-month civil war, an estimate that surpasses previous reports.

Jamie McGoldrick, a UN humanitarian official and the agency’s representative to Yemen, said the new estimate is based on statistics from medical facilities in the country—a number that may rise as many people are often buried without official records, Reuters reports. Previous estimates ranged between 4,000 and 9,000 casualties.

“We know the numbers are much higher but we can’t tell you by how much," McGoldrick told reporters Tuesday at a news conference in the capital city of Sanaa. “The figures we have are probably incomplete because we take the numbers from functioning health services, and in some of these areas there are no functioning health services.”

Medical facilities, where they exist in the country, have not been immune to the escalation in hostilities. A Médecins Sans Frontières (Doctors Without Borders) hospital was bombed in northern Yemen this month, killing 11 people and wounding 19. The medical charity said it was the fourth attack against one of their facilities in less than a year, further endangering the already limited access to health care in the country.