Somali militants ambushed an aid convoy, killing a Kenyan aid worker and kidnapping four international workers at a Kenyan refugee camp near the border with Somalia, officials have said.

Four international workers from the Norwegian Refugee Council were abducted on Friday after gunmen attacked a two-car convoy traveling through the sprawling Dadaab refugee camp, said police official Philip Ndolo.

Al Jazeera's Nazanine Moshiri said the kidnapped workers are nationals of Norway, Canada, Pakistan and the Philippines.

"We understand that this was a high-level delegation that was touring the camp on its outskirts when they came under an organised ambush of about a dozen Somali armed men. One vehicle got away and they other was taken and driven toward the Somalia border some 80 miles away," our correspondent said.

"The vehicle was abandoned and it is unclear if the abducted workers were put in another vehicle and their whereabouts are still unknown", she added.

Elisabeth Rasmusson, secretary-general of the NRC, was travelling in the convoy when it was attacked.

"We had just left the camp and we were just going out towards the ... main road towards Dadaab city, and that is where we were attacked. So we were actually attacked in what is recognised as the safe part of the camp," Rasmusson said.

"We were attacked by, I think it was four people and they were armed, and they were armed with pistols as far as I could see, they were shooting and what happened is that they managed to take one car and we know now, what we know is that four of our expatriate colleagues are not accounted for," she added.

The gunmen killed a Kenyan driver for the aid group during the attack, Ndolo said. Earlier reports said one Kenyan driver was also kidnapped but a security official said only the four foreign workers were taken.

Dadaab hosts nearly 500,000 Somali refugees.

Ndolo said that police and military security personnel were pursuing the attackers.

Kenya deployed troops into Somalia last October, so even if the kidnappers succeed in crossing back into Somalia, they may have to contend with Kenyan troops on the other side of the border.

Attackers unknown

A Norwegian Refugee Council spokesman in Norway, Rolf Vestvik, said he could not yet confirm any of the details of the incident.

However, Vestvik did say that the Norwegian Refugee Council's Secretary General Elisabeth Rasmusson was in Dadaab during the attack. Vestvik said Rasmusson is safe and unharmed.

A spate of kidnapping attacks carried out by Somali gunmen last year were one of the reasons Kenya used to publicly justify its military push into Somalia.

Last October, gunmen entered Dadaab and snatched two Spanish women working for Doctors Without Borders. The two are still being held, likely in Somalia. Gunmen also carried out kidnapping attacks around the coastal resort town of Lamu.

Despite the presence of Kenyan military troops, al-Shabab militants still control wide swaths of southern Somalia, and if the kidnappers make it into that region the hostages could be in for a long ordeal.

No claim of responsibility was immediately made after Friday's attack.

Source: Agencies