Nairobi, Kenya (CNN) -- The medical charity Medicins Sans Frontieres -- also known as Doctors without Borders -- said Friday the abduction of two of its workers is jeopardizing assistance to refugees in Kenya.
The Spanish women were part of the MSF's international staff, officials said.
MSF identified the victims as Montserrat Serra, 40, of Girona, and Blanca Thiebaut, 30, of Madrid. They were working as logisticians at the Dadaab camp complex.
In a statement, the organization said it has been unable to contact the pair and asked media to respect the privacy of their families.
"We are doing all we can to ensure their safe and swift return," said Jose Antonio Bastos, president of MSF in Spain.
The attack took place in a new camp known as Ifo 3, an MSF staffer said Thursday. He said the two women as well as their pickup truck were missing. The driver, shot in the neck, was in stable condition at a hospital.
He was identified Friday as Mohamed Hassan Borle, 31.
MSF has evacuated part of its team working in Dagahaley and Ifo, two of the three refugee camps in Dadaab, the statement said.
"As a consequence, crucial medical activities had to be stopped," the statement noted. However, MSF is still maintaining its lifesaving activities."
Dadaab, about 80 kilometers from the Somali border, is the largest refugee complex in the world. It houses thousands of people who have fled war and famine in the Horn of Africa.
United Nations staff and international aid workers often travel with armed Kenyan police escorts from their bases to the various camps. They are not allowed, under their regulations, to travel on their own.
However, MSF usually operates without a security escort. The medical humanitarian organization delivers emergency aid to people affected by war, epidemics and disasters.
A Kenyan driver from Care International was abducted in September in a nearby camp and is still missing.
Aid workers have long worried about security in Dadaab, particularly since the refugee processing center at the border has been closed by the Kenyan government for several years.
"Virtually anybody could be arriving in Dadaab," a U.N. official said.