As violence and uncertainty continues in Yemen, there is an increasing focus on the impact of tribal alliances.

Sadeq Al Ahmar is the leader of the Hashid Tribal Federation, commanding the loyalty of hundreds of thousands of people under the umbrella of nine tribes including the president's own, the Sanhan.

His family controls big businesses, owning a phone company, a bank, a TV network and franchises for food chains including KFC.

The tribe has strongly supported Yemeni president Ali Abdullah Saleh in the past, but Al Ahmar has publicly accused Saleh of not doing enough, and taking advantage of a joint US-Yemen anti-terror campaign to feed his personal financial interests.

With reports of tribal fighters taking over military bases outside Yemen's capital, the role of the Hashid Tribal Federation in Yemen's future has never been in sharper focus.

Al Jazeera's Charles Stratford reports.