The president of the Spanish branch of Medicins Sans Frontieres, or Doctors Without Borders, has identified the two MSF collaborators kidnapped from a Somali refugee camp in Kenya as Blanca Thiebaut and Montserrat Serra.

MSF has been in contact with the women's families and with "all the relevant authorities since the first moment," Jose Antonio Bastos said Friday at a press conference in Madrid.

He said MSF was working "hand in hand" with the Spanish Foreign Ministry to secure the safe return of the aid workers.

Thiebaut, 30, and Serra, 40, were part of the MSF logistics team at the camp in the eastern Kenyan town of Dadaab, about 100 kilometers (60 miles) from the Somali border.

They were taken at gunpoint at 1:30 p.m. Thursday while traveling in a vehicle driven by Mohamed Hassan Borle, who was wounded in the attack, but is out of danger, Bastos said.

He said MSF has not heard from the kidnapped women and has no idea of their condition or of the identity of their captors.

The 49 international volunteers in the MSF team at Dadaab have withdrawn to Nairobi pending a decision about when they will be able to resume their work, Bastos said.

He said the abduction of Thiebaut and Serra would not lead MSF to revise its policy of operating without armed security.

"We have many years working in countries at war and we have a proportion of security incidents very similar to that of other NGOs that go with armed escorts," he said.

Denying that MSF had been warned by Kenyan authorities about a possible worsening security situation around Dadaab, he said the area has been very dangerous since 1991, when Somalia slid into civil war.

Bastos stressed the need for "prudence and discretion" in the situation.

"If we formulate a theory about the authorship (of the kidnapping), this is a very clear example of the information that could jeopardize the quick resolution of this incident," he said, urging all involved parties to refrain from public comments of that nature.

Authorities in Nairobi strongly suspect the two Spanish aid workers are still in Kenya, a police spokesman told Efe earlier Friday.

"It rained a lot yesterday. Even the vehicles they (the kidnappers) use were getting stuck in the mud. We have closed all the routes that lead to Somalia," Charles Owino said.

"We have deployed a contingent of soldiers and police, as well as specialized paramilitaries well-trained in rescue missions," the Kenyan official said.

Kenyan police will use "all possible means" to rescue the captives, Owino said. "It's the high season for tourism in this country. This is a serious event. We don't take it lightly."

Dadaab is thought to be the largest refugee camp in the world, housing nearly 445,000 people who have fled conflict and famine in Somalia, U.N. officials say.