Yemeni military officials say al-Qaida's local affiliate has captured three towns near the southern port city of Aden, where pro-government forces have been advancing against Shiite rebels in recent weeks.

Witnesses say al-Qaida's black banners are flying over buildings in the towns of Rabat, al-Lahoum and al-Masaabin on Thursday.

The security officials say the extremist group seized government buildings without a fight and turned them into military bases.

The officials spoke on condition of anonymity because they were not authorized to speak to the media. The witnesses did not want to be identified, fearing reprisals.

Yemen's armed forces have splintered over the conflict with the rebels, known as Houthis, allowing the local al-Qaida branch, which is also battling the rebels, to capture territory.