// BBC WORLD NEWS — MONDO
Lightning Houthi advance in Yemen may bring dangerous new dimension to Iran war
Saudi-backed Yemeni forces have been struggling to contain Houthi advances
The Houthis' lightning advance across the southern reaches of the Tihamah – Yemen's arid coastal plain – appears to have taken most observers by surprise.
Until recently, the anti-Houthi coalition known as the National Resistance held significant territory along Yemen's Red Sea coast. In a matter of days, much of this has fallen to the Houthis.
According to some estimates, the Iranian-backed rebels have captured as much as 130km (81 miles) of the country's strategically important coastline.
It's the group's most impressive military coup for several years, proving that despite a civil war that has lasted 12 years, devastating Saudi air raids and attacks by American, Israeli and British forces, the Houthis remain a force to be reckoned with.
With their opponents stunned and demoralised, it's unlikely the Houthis will be dislodged any time soon.
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"Now that they are there, they're going to be entrenched," Hisham al-Omeisi, senior analyst at the Brussels-based European Institute of Peace, told the BBC. "And it's going to be a lot more costly to push them out."
Of course, the Houthis are not alone. They enjoy the backing of Iran, support that has become even more important for Tehran in the wake of the setbacks and defeats experienced by other parts of its so-called "Axis of Resistance" – Lebanese Hezbollah, Hamas in Gaza and the Assad regime in Syria.