DUBAI • Yemen has endured thousands of air strikes and the deaths of more than 10,000 people in a 19-month war that has also unleashed hunger on the desperately poor country - but its biggest challenge may be yet to come.
The conflict has led to Yemen's de facto partition, with rival armies and institutions in the north and south, and could mean the map of the Middle East having to be redrawn again.
Saudi-led coalition air strikes on rebel-held buildings hit Yemen's west yesterday, killing 60 people.
Meanwhile, a three-day truce to allow in more humanitarian aid and prepare a political settlement collapsed last week, reflecting deadlocked efforts to end the stalemate.
But behind the combatants' disagreements over how to share power, Yemen's future as a unified state appears increasingly in doubt.
Such a possibility appeared remote when a coalition of Arab states began launching air strikes in March last year to restore to power President Abedrabbo Mansour Hadi, driven from the capital, Sanaa, by the Iranian-allied Houthi movement in 2014.
It seems less fanciful now.
The Houthis' rise to power in the north has provoked a revival of southern separatism, a movement that sees the fracturing of state power as its moment to break away. At the same time, the south and its major city, Aden, serve as a base for the internationally recognised government, which is trying to take back national control even as it manages an uneasy alliance with the secessionists.
Yemen was once split between a pro-Soviet state in the South and a republic buttressed by armed tribes in the North. A southern bid to secede failed in 1994 when the north restored unity by force.
Many southerners now believe their time has come after two decades of what they see as marginalisation within the unified state, and the plundering of mostly southern oil reserves by corrupt northern tribal sheikhs and politicians.
Southern soldier Faisal al-Salmi said he and his comrades were ready to die to be rid of the northerners. "We have become an independent state thanks to God and the leadership of the Arab coalition... southern lands have been liberated by the blood of her sons and have loosed the bonds of unity which brought only terrorism, cronyism, and the looting of the people's wealth," Mr Salmi told Reuters.
A split could bring more instability along one of the world's busiest shipping lanes, perhaps by setting the scene for a fight over the south's oilfields, or by triggering, as in 1994, efforts by the north to dominate the south.
For now, both sides appear to be setting up parallel institutions that could pave the way for an enduring divorce. The government moved to Aden from Saudi exile in September while the Houthis formed their own government in Sanaa this month.