Several others were wounded in firefights that erupted Tuesday between Al-Butahif tribesmen from the eastern Marib province and the Belhareth from adjacent Shabwa province, the sources told AFP.
The two tribes are locked in a dispute over the ownership of a desert area between both provinces, and which they believe to be rich in oil.
Six Al-Butahif members and nine Belhareth were killed in the clashes during which both light and medium weapons were used, the sources said.
There are millions of firearms in the deeply tribal Arabian Peninsula country, with an estimated average of three weapons per person.