In Washington and Riyadh, there’s growing momentum behind efforts to end Yemen’s war. But in the mountains that guard the conflict’s latest prize, it’s the fighting that is intensifying and it could make diplomacy futile.

"We don’t care about all this talk of peace,” said Abdulrehman Ahmed, a soldier with Yemeni government forces repulsing a push by Iran-backed Houthi fighters to capture oil-rich Marib province. "We’re fully ready to fight until the end.”

Ahmed’s on the most volatile front line of a war that’s spread death, disease and hunger for six years, fueled by the Middle East’s predominant feud between U.S. ally Saudi Arabia and foe Iran.