Kenyan security forces on Saturday scoured border regions with war-torn Somalia in the hunt for armed kidnappers who seized four foreign aid workers from Dadaab, the world’s largest refugee camp. The two men and two women who work with the Norwegian Refugee Council (NRC), come from Canada, Norway, Pakistan and the Philippines. A Kenyan driver was killed and two others were wounded during Friday’s attack. “The search is intensifying and more security forces have been sent to make every effort possible but, so far, no one has been recovered,” Kenyan army spokesman Cyrus Oguna told AFP. Aerial searches were ongoing using both military helicopters and aircraft, while vehicles and troops on foot searched the remote scrubland either side of the porous border with Somalia. Kenya, which invaded southern Somalia in October to attack Al-Qaeda linked Islamist insurgents, has troops some 120 kilometres (75 miles) deep into Somalia. However, the forces control only pockets of the vast territory. While many fear the gunmen and their hostages crossed swiftly into Somalia — only some 100 kilometres from Dadaab — Oguna said he was still hopeful they remained inside Kenya. “We are thinking that they are in Kenya, we are making every effort that we can, and we are hopeful of a positive outcome,” he added. The aid workers’ vehicle, which the gunmen stole after killing the driver, was found abandoned a few hours after the attack. Similar abductions in the past have seen the gunmen disappear into the bush to evade capture.