Yemen crisis: Who is fighting whom? -- BBC

Yemen is in the grip of its most severe crisis in years, as competing forces fight for control of the country.
Impoverished but strategically important, the tussle for power in Yemen has serious implications for the region and the security of the West.  Here are some key questions explained.   
Who is fighting whom? In recent months Yemen has descended into conflicts between several different groups, pushing the country "to the edge of civil war", according to the UN's special adviser.
The main fight is between forces loyal to the beleaguered President, Abdrabbuh Mansour Hadi, and those allied to Zaidi Shia rebels known as Houthis, who forced Mr Hadi to flee the capital Sanaa in February.

Yemen's security forces have split loyalties, with some units backing Mr Hadi, and others the Houthis and Mr Hadi's predecessor Ali Abdullah Saleh, who has remained politically influential. Mr Hadi is also supported in the predominantly Sunni south of the country by militia known as Popular Resistance Committees and local tribesmen.

Both President Hadi and the Houthis are opposed by al-Qaeda in the Arabian Peninsula (AQAP), which has staged numerous deadly attacks from its strongholds in the south and south-east.

The picture is further complicated by the emergence in late 2014 of a Yemen affiliate of the jihadist group Islamic State, which seeks to eclipse AQAP and claims it carried out a series of suicide bombings in Sanaa in March 2015.

After rebel forces closed in on the president's southern stronghold of Aden in late March, a coalition led by Saudi Arabia responded to a request by Mr Hadi to intervene and launched air strikes on Houthi targets. The coalition comprises five Gulf Arab states and Jordan, Egypt, Morocco, Pakistan and Sudan.

Why does it matter for the rest of the world?

What happens in Yemen can greatly exacerbate regional tensions. It also worries the West because of the threat of attacks emanating from the country as it becomes more unstable.

The conflict between the Houthis and the elected government is also seen as part of a regional power struggle between Shia-ruled Iran and Sunni-ruled Saudi Arabia, which shares a long border with Yemen.

Gulf Arab states have accused Iran of backing the Houthis financially and militarily, though Iran has denied this, and they are themselves backers of President Hadi.

Yemen is strategically important because it sits on the Bab al-Mandab strait, a narrow waterway linking the Red Sea with the Gulf of Aden, through which much of the world's oil shipments pass. Egypt and Saudi Arabia fear a Houthi takeover would threaten free passage through the strait.  Read More 

Yemen crisis: Who is fighting whom? - BBC News

Yemen crisis: Who are the Houthi rebels? - Telegraph

Who are the Houthis in Yemen? - Al Jazeera English