Security officials say 57 militants, mostly from al—Qaeda, have escaped from a prison in southern Yemen.

They say the 57 were among 62 inmates from the Mukalla jail in the Hadarmout province who escaped on Wednesday through an underground tunnel.

Bands of gunmen attacked the prison simultaneously, opening fire on the guards from outside to divert their attention away from the escape.

One guard was killed and another wounded in the attack, said the security officials, who spoke on condition of anonymity because they were not authorized to speak to the media.

Wednesday’s escape was the latest sign that Yemen’s months—long upheaval has emboldened al—Qaeda militants to challenge authorities in the country’s nearly lawless south.

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