Yemeni forces have killed what they say are 500 suspected al-Qaeda militants in an all-out offensive against them in their southern strongholds that began on 29 April.
Forty soldiers were killed and another 100 wounded in the operation in the provinces of Shabwa and Abyan, in which 39 militants were captured, Colonel Saeed al-Fakeih told reporters.
"We will press on with our war against Al-Qaeda, especially in the regions that [militants] fled to," he said.
The army launched the offensive against Al-Qaeda in Shabwa and neighbouring Abyan in a bid to expel its forces from smaller towns and villages that escaped a previous sweep in 2012.
Troops and militia have entered a series of towns, but analysts say their advances could be the result of a tactical retreat by the militants in coordination with local tribes.
Taking advantage of a collapse of central authority during a 2011 uprising that forced veteran strongman Ali Abdullah Saleh from power, al-Qaeda seized large swathes of the south and east.
They remain deeply entrenched in Hadramawt province further east, where they have carried out a series of spectacular attacks in recent months.