Mogadishu: Two more aid workers in Somalia have been kidnapped by gunmen in the latest attack on humanitarian workers, locals said on Tuesday.

About a dozen men with rifles stopped the Somali aid workers on their way to Mogadishu on Monday and turned their two cars into bush near Afgooye, west of the capital, witnesses said.

"I could see the two cars marked 'WFL' being hijacked," bus-driver Hassan Osman said.

The regional governor confirmed the armed men seized a Somali man and woman working for foreign charity Water For Life.

Four foreign aid workers abducted in April are still being held.

Two UN workers from Sweden and Denmark were briefly taken on Saturday in south Somalia, until local officials were able to negotiate their release with Islamists.