Somali gunmen on Tuesday kidnapped two contractors, a Briton and a Kenyan, working for a U.N.-funded project in southern Somalia, the United Nations said.

Local militias were pursuing the kidnappers in the hope of freeing the captives, residents said, and local clan elders were pressing the gunmen to release the two men.

"Two foreign nationals - a Briton and a Kenyan - were abducted this morning by unknown gunmen between Saakow and Bu'aale in Middle Juba," the U.N. country office for Somalia said in a statement.

The two work for Genesys International Corporation Ltd of Bangalore, India, which has been hired by the U.N. Food and Agriculture Organisation to carry out a survey of the Juba and Shabelle rivers, the statement said.

It did not give their names. A call to Genesys offices in Bangalore was not answered.

"Witnesses on the ground say there was gunfire when the men were taken, but there is no information to suggest that any serious injury was sustained by either man," it said, referring to reports that one of the men had been wounded.

The two are being held in or near the town of Jilib, and "clan elders and community leaders who do not condone such abductions are putting pressure on the perpetrators to release the men," the statement said.

Local elders and militiamen pursued the kidnappers toward Jilib district, 280 km (175 miles) south of Mogadishu.

"These foreign men have been in Sakow for three days, there is no tight administration there and they have not contacted us over their security. We are just trying our best to free them safely," regional chairman Ibrahim Noleye said.

Kidnapping is a lucrative business for Somali criminals, who usually treat their captives well, seeing them as investments on which they expect to earn a good return in the form of ransom.

But kidnapping is relatively rare in southern Somalia as the region is too dangerous for most aid workers. Most abductions for ransom in the past year have taken place in the safer northern parts of Somalia, which are relatively stable.