"I consider Taez to have fallen under the control" of the dissidents, sheikh Hammoud Saeed al-Mikhlafi, the head of the tribal council in Taez told AFP by telephone.
Earlier, heavy clashes between troops and suspected al-Qaeda gunmen at the gates of the southern Yemen city of Zinjibar left 15 people dead, nine of them government soldiers.
The fighting erupted overnight when troops advanced on the capital of Abyan province, as they prepared to wrest it back from the control of suspected al-Qaeda militants, who overran most of it
on May 29.
"Heavy fighting broke out between the army and Al-Qaeda gunmen when troops advanced towards the city to storm it," said a military official, giving a toll of nine soldiers dead and at least 10 wounded.
The two sides blasted each other with machine guns, artillery rounds and mortar shells.
Yemen is in crisis with the departure of the President for medical reasons, after he was injured in a rebel attack.
Scores of people were killed in running battles over the last week, following months of unrest and widespread demonstrations.
