A spokesman for Somalia's Islamic extremists says their rebels will fight the British troops that are to be deployed to the country as peacekeepers.

Sheikh Ali Mohamud Rage, a spokesman for al-Shabab, said on the the group's radio Tuesday that their fighters would welcome the British troops with bullets and drag beheaded British soldiers through the streets.

His comments were in response to British prime minister David Cameron's pledge last month that as many as 70 British military personnel could be sent to Somalia to bolster a United Nations-backed mission to support the Somali government against the extremists.

It would be the first time Britain has formally joined the international contingent backing the African Union's long-running efforts against al-Shabab, which is linked to al-Qaida.