The recent spate of kidnappings have raised tensions on the Kenya-Somalia border [Reuters]

Somali gunmen have kidnapped three employees of the Danish Demining Group working in northern Somalia, according to officials, the latest in a series of abductions in the nation.

A 60-year-old Danish man, 32-year-old American woman and a male Somali colleague were abducted on Tuesday near the Puntland capital of Galkayo, where the demining group has been in operation since 2007. Local security officer Ali Mohamed told the AFP news agency the aid workers were kidnapped from near the airport at Galkayo.

Galkayo, which straddles the border between Puntland and the self-proclaimed separate region of Galmudug in central Somalia, saw heavy fighting last month between rival political or clan groups.

Al Jazeera's Peter Greste, reporting from Nairobi, said it was still too early to know who was behind the abductions, but added that the impact to humanitarian groups working in the area could be immense.

"The collective response of aid agencies will be to take a long, hard look at their security plans and the places and ways they are working. It is starting to look like a very dangerous place to work," said Greste.

Kenya kidnappings

The kidnapping come only weeks after the seizure of two Spanish women working for Medecins Sans Frontieres from a refugee camp in neighbouring Kenya, as well as the kidnappings of two European tourists from Kenya's coast. Somali gunmen were suspected in those attacks.

Greste said: "It is difficult to say if these [kidnappings] are related or not. They don't appear to be but we'll just have to wait and see if any ransom demands come with this."

One of the European tourists, a French woman named Marie Dedieu, who was suffering from cancer and heart disease, died while in the custody of the kidnappers.

Dedieu was captured from an island resort near the northern Kenyan town of Lamu on October 1. Kenya's government blamed the attack on Somali fighters from the al-Shabab group.

Criminal gangs

Kenya has sent an estimated 1,600 forces into southern Somalia in pursuit of al-Shabab fighters in response to those kidnappings, although al-Shabab has denied responsibility for the abductions.

The northern semi-autonomous province of Puntland is generally considered more stable than the rest of Somalia, which is a battleground between disparate armed groups and the weak UN-backed government in the capital.

Somalia is one of the world's most dangerous regions for aid workers. It is also home to a number of pirate gangs who earn a living by seizing boats, but who have recently been accused of capturing hostages on land as well.

A lack of effective central government since Somalia plunged into civil war two decades ago has allowed a flourishing of militias, Islamist insurgencies and criminal gangs.