Yemen's Houthi rebels have advanced towards Aden, where President Abd-Rabbu Mansour Hadi has been holed up since fleeing the capital Sanaa last month.
Before moving closer to the coastal city on Wednesday, rebels seized an airbase that until a few days ago was used by US troops deployed in the fight against al-Qaeda.
The al-Anad base, 60km from Aden, had since been occupied by Yemeni government forces.
The advance of the Houthis threatens to plunge the Arab world's poorest country into a civil war that could draw in its Gulf neighbours. Already, Hadi has asked the UN to authorise a foreign military intervention in the country.