Gunmen kidnap two foreign aid workers in Somalia

* Armed men seize MSF-Belgium staff, vehicle

* Belgian and Dane believed to be among captives

* Masked gunmen shoot dead local aid worker

(Corrects throughout to reflect information from CARE that man shot dead is a former employee of the agency and that it suspended operations in south-central Somalia)

By Abdi Sheikh and Mohamed Ahmed

MOGADISHU, April 19 (Reuters) - Gunmen kidnapped three aid workers, believed to include a Belgian and a Dutchman, in central Somalia on Sunday, a colleague and a local elder said.

In a separate incident masked gunmen killed a former local employee of another charity in the central town of Merka, witnesses said.

Attacks on aid workers in Somalia, which are normally blamed on hardline Islamist rebels and clan militia, have cut the ability of relief agencies to respond to a humanitarian crisis that many say is Africa's most acute.

Local elder Hassan Maalin told Reuters by telephone from central Somalia: "Unidentified armed men kidnapped two MSF-Belgium aid workers in Bakol region."

MSF in Brussels said it had lost contact with a medical team in the area and was seeking more information.

"The team includes two international staff, one Belgian and one Dutch. We are contacting the families. For now we cannot give any names," it said in a statement.

A local MSF worker in Somalia who asked not to be named said three aid workers, incuding a Belgian and a Somali, had been seized along with their car and Somali bodyguards.

He had earlier identified the third aid worker as a Dane.

"They were heading to Hudur, the capital of Bakol, when gunmen took them away in their vehicle," he said, adding that they had been carrying out a nutrition study in Rabdhure town.

Separately, masked gunmen killed a former local employee of aid agency CARE International, in Merka, 90 km (56 miles) south of the capital Mogadishu.

"Omar Sharif ... was shot dead near the mosque. Masked gunmen shot him in the head and he died on the spot," Merka resident Ahmed Hussein by telephone.

CARE suspended all activities in South-Central Somalia in October, 2008, after a threat from a militant group.

Somalia has been mired in civil conflict for 18 years and is one of the most dangerous countries in the world.

Aid workers and journalists have often been kidnapped in the lawless Horn of Africa nation. Hostages are generally relatively well treated and released, often after a ransom is paid.

More than 1 million Somalis have been uprooted in the last two years by fighting, and more than 3 million -- about a third of the population -- depend on emergency food aid.

The kidnappers have also struck on and across the border with neighbouring Kenya. Islamist rebels seized five Kenyans on the frontier last month, but later freed them. [ID:nLS428423]

In February, two elderly Italian nuns were released by Somali gunmen who had kidnapped them during a cross-border raid into Kenya in November 2008. [ID:nLJ584911] (Additional reporting by Ibrahim Mohamed in Mogadishu and Jan Strupczewski in Brussels; Writing by Daniel Wallis)