Forty militants have been killed in two days of air strikes by Yemeni forces in the southern province of Abyan, Yemen's state news agency Saba says.
Two soldiers were also killed as Yemeni troops retaliated against al-Qaeda militants who stormed army camp.
The unrest is part of widening chaos in Yemen since protests broke out in February against the 33-year rule of President Ali Abdullah Saleh.
He is being treated in Saudi Arabia after an attack on his palace in June.
Speaking in Riyadh on Tuesday, the Saudi foreign minister, Prince Saud al-Faisal, said the health of the Yemeni president was "generally good".
He gave no further details on the 64-year-old leader's condition or plans.
A battle has been raging for weeks in the southern town of Zinjibar, capital of Abyan province, where militants have exploited the political vacuum to move into Zinjibar and the town of Jaar. Thousands have fled to neighbouring Aden province.
Opposition groups accuse the Sanaa government of failing to secure the area to play up a jihadist threat in an attempt to shore up Western support for Mr Saleh as the guardian of Yemen's stability.
Mr Saleh has refused to sign a Gulf-mediated transition plan that would see him step down from power in return for immunity from prosecution for the deaths of dozens of protesters in the five-month uprising against his regime, which the opposition views as authoritarian, corrupt and nepotistic.
Western diplomats in Sanaa have said there is little chance Mr Saleh will return, but Yemeni officials insist that no transfer of power will take place until he is back on Yemeni soil.
Tribal fighting in the capital in May pushed the country to the brink of a civil war, while the violence raging in the south has sparked fears of a humanitarian crisis in the impoverished and unstable Gulf Arab republic.