SANAA, Yemen — Yemen’s pro-government troops fought pockets of resistance outside a key military base in the country’s south Tuesday, a day after they seized it from Shiite rebels, military officials said. The capture of the Al-Anad base — once the site of U.S. intelligence operations against al Qaeda’s powerful Yemeni affiliate — was a significant victory for the forces allied to Yemen’s exiled President Abed Rabu Mansour Hadi in their battle to reverse the gains of the rebels known as Houthis. The base was taken by the rebels when the conflict intensified in the spring and was their main encampment in the country’s south.