Dozens of suspected al Qaeda militants escaped from a jail in the Yemeni city of Mukalla Wednesday, according to a senior security official.
CNN could not independently verify that the escapees were members of al Qaeda.
A soldier and a prisoner were killed and two soldiers were injured in the incident, said the security official who asked to remain anonymous because he is not authorized to speak to the media.
Armed militants began attacking the prison at about 8 a.m. Wednesday, witnesses said. They fired heavy artillery before the escape.
Recent clashes in the southern province of Abyan killed seven Yemeni soldiers and 17 militants. The fighting was mainly concentrated in the cities of Zinjibar and Jaar.
Government troops have been battling both anti-government tribal forces and Islamic militants, including al Qaeda in the Arabian Peninsula.
The United States has been aiding Yemen's military in its fight against Islamic militants amid fears that al Qaeda is exploiting the political chaos and leadership vacuum engulfing the unstable and impoverished Arabian Peninsula country.
Jeffrey Feltman, U.s. assistant secretary for Near Eastern Affairs was scheduled to meet with senior Yemeni officials during a visit to Yemen Wednesday.
Widespread tumult has engulfed Yemen for months, with thousands of demonstrators who oppose the rule of Ali Abdullah Saleh urging the president's departure. Saleh was taken to Saudi Arabia for treatment after injuries suffered in an attack on his compound.
Saleh's party said Tuesday that he planned to return to Yemen on Friday. Opposition leaders called news of Saleh's return false rumors.