Two foreign contractors, a Briton and a Kenyan, working for the UN in Somalia have been seized by unknown gunmen in southern Somalia, reports say.

They were doing work for the UN Food and Agriculture Organisation.

The incident happened on a road between the towns of Bu'aale and Sikow in the Juba region of Somalia, when gunmen fired on the men's car, witnesses say.

The UN based in neighbouring Kenya says it cannot confirm the kidnapping, although it had confirmed it earlier.

A number of foreign aid workers have been kidnapped in Somalia in the past few months.

It is not known why the two men, who are believed to be working for the FAO-funded Somalia Water and Land Information Management project, may have been kidnapped.

In February, MSF withdrew all its international staff from Somalia after three of its workers were killed by a bomb.