SAN JUAN, Puerto Rico (AP) — Doctors Without Borders found two public hospitals in good condition after the powerful earthquake that devastated Haiti’s capital, and officials with the group said Wednesday they would begin treating about 500 people who need emergency surgery.

But one of the mission’s directors said the humanitarian group doesn’t have enough medical staff, equipment and medicine to properly care for the injured. The mission has about 800 medical workers in Haiti, but a large number haven’t been located since Tuesday’s quake, Stefano Zannini said.

“Most of them are dispersed somewhere, are lost somewhere,” he told The Associated Press in a phone interview. “We are not sure where they are.”

About 800 injured people have come to the mission’s offices for treatment, Zannini said. They’ve scattered themselves around a courtyard, sleeping in tents, on top of rugs, on the floor and on plastic sheeting, waiting to be transferred to one of the two hospitals identified as being safe enough to withstand the aftershocks that have rattled Haiti.

“We saw every kind of person: Women, men, young, old, children, pregnant women coming and asking for help,” Zannini said.

More than 500 people need immediate surgical intervention. But in the next couple of days, the mission will run out of gasoline to transport patients and food and water, Zannini said.

Doctors Without Borders said earlier in the day that hundreds of Haitians were being treated in tents for broken bones, burns and other less-serious injuries.

Several area hospitals collapsed in the earthquake, and authorities haven’t determined how many other hospitals were left standing around the capital.