The official said three government soldiers died and four were wounded in the fighting, part of an offensive that began earlier this month to uproot Islamist militants from southern Yemen.
He said many of the dead militants were Somalis, but gave no precise figures.
Al Qaeda-linked Ansar al-Sharia (Partisans of Islamic Law)have exploited last year's popular protests against President Ali Abdullah Saleh's 33-years in office and captured large swathes of territory in the province of Abyan, including the provincial capital Zinjibar.
The expansion of the militants' area of control has unsettled the United States and Saudi Arabia, both targets of failed attacks by Yemen's al Qaeda wing which earlier this week claimed responsibility for a suicide bombing in Sanaa on Monday that killed more than 100 soldiers.
Both countries have been pushing new Yemeni President Abd-Rabbu Hadi Mansour, who took over after Saleh stepped down in February, to unite the army and roll back the militants' gains.
Washington considers Qaeda in Yemen, which has attracted foreign fighters from places like Somalia and Saudi Arabia, the world's most active terror cell.
Yemeni forces last week recaptured parts of the strategic city of Zinjibar and fought militants in the city of Jaar, another militant stronghold, leaving 33 militants and nine soldiers dead.
(Reporting by Mohammed Mukhashaf; Writing by Mahmoud Habboush; Editing by Sami Aboudi and Sophie Hares)