Yemen’s top factions are squaring off for battle after months of skirmishes, turning respectively to neighbouring Saudi Arabia and its regional rival Iran for help in what may become all-out war.

With President Abd-Rabbu Mansour Hadi seeking a comeback from the port city of Aden while the Shia Houthi movement controls the capital, Sanaa, rival administrations are trading bellicose rhetoric as fighting intensifies and factions commandeer airfields for the next stage of the struggle.