Nairobi, Kenya (CNN) -- Four aid workers, who were abducted from Kenya's vast Dadaab refugee complex near the Somali border last week, were freed late Sunday during a shootout with kidnappers, a military official said..
Kenya Defense Force soldiers, working with Somali government troops, confronted the abductors after tips from local residents, Col. Cyrus Oguna said. One of the kidnappers was killed, and two escaped when they tried to flee with their hostages.
The workers, a Norwegian, Pakistani, Filipino and Canadian, were taken to a military base in Dhobley, Somalia, he said. Although none of them were hurt in Sunday's gunfight, the Pakistani was shot in the leg during the kidnapping and underwent surgery at the base. Details on his condition were not immediately available.
Several days on the run took its toll on the workers.
"They were tired, fatigued, hungry and unwell," Oguna said. "The kidnappers were making them walk during the night and hide during the day."
All work for the Norwegian Refugee Council, a European aid group.
"The Norwegian Refugee Council is relieved and pleased to confirm that our four abducted colleagues are found and released," according to the global humanitarian agency's website.
The aid group said the workers' families have been notified and more information will be released later.
The council has released few details about the kidnappings.
"In our experience with these types of incidents, the less information we provide on the identity of those abducted, the better," agency spokesman Rolf Vestvik said Friday.
The aid agency said only that a convoy "was involved in an incident" in Dadaab and that Secretary-General Elisabeth Rasmusson and Country Director Hassan Khaire were at the camp but neither was in the convoy.
While the four aid workers were taken, their Kenyan driver was killed, police said Friday.
Two other staff members were injured and treated at a hospital in the capital of Nairobi, officials said. A Norwegian Refugee Council vehicle also was taken.
Police have not said whether the kidnappers were from Al-Shabaab, an al Qaeda-linked group that is fighting to impose Islamic law in Somalia and controls large parts of the troubled nation.
Kenya has blamed previous abductions of tourists and aid workers on Al-Shabaab.
In September, armed bandits broke into a beachfront cottage where Britons Judith and David Tebbutt, both in their 50s, were staying. David Tebbutt was shot dead while trying to resist the attack. His wife was grabbed and spirited away on a speedboat. She was released months later in Somalia after her family paid a ransom.
In October, pirates made another cross-border raid, this time snatching a French woman in her 60s, who used a wheelchair and was believed to be in bad health, from a holiday home on Manda Island, where she lived part of the year. She later died, likely because of the kidnappers' refusal to give her medicine, according to the French Foreign Ministry.
Also in October, gunmen abducted two Spanish workers with the medical charity Doctors Without Borders from Dadaab, the world's largest refugee camp, which houses nearly 500,000 people about 50 miles west of the Somali border.
CNN's Elizabeth Joseph and Journalist Lillian Leposo contributed to this report.