NAIROBI, Kenya (AP) — A police official says Kenyan troops and six helicopters have been deployed to the Somali border in hopes of finding two Spanish women kidnapped by Somali gunmen. The searchers found their vehicle was found stuck in the desert.

Police suspect the gunmen may have forced the women to walk. The police official said Friday that the hijacked vehicle with two Spaniards from the aid group Doctors Without Borders got stuck about 20 miles (30 kilometers) from the Somali border because of rain and bad terrain. The official said he could not be named.

The gunmen kidnapped the women from the world’s largest refugee camp Thursday.

The U.N. has temporarily suspended all non-lifesaving aid operations in the world’s biggest refugee camp following the kidnapping of two Spanish aid workers near the Kenya-Somalia border, a spokeswoman said Friday.

Hundreds of staff have been confined to their offices, forcing the cancellation of services like education, counseling and relocation of families until further notice.

“Only water, food and health services are being maintained,” said U.N. refugee agency spokeswoman Needa Jehu-Hoyah. “This will of course have an impact on the poor refugees.”

In recent months, tens of thousands of refugees fleeing a spreading famine in southern Somalia have swollen the severely overcrowded camp.