Sana'a: Security officials say at least 40 Al Qaida militants have escaped from a jail in southern Yemen.

The militants attacked their guards and seized their arms early on Wednesday just as bands of heavily armed militants attacked the prison in the city of Mukalla on the Arabian Sea.

The officials said those who escaped included militants convicted on terror charges or held in protective custody pending their trial.

The officials spoke on condition of anonymity because they were not authorised to speak to the media.

Wednesday's escape was the latest sign that Yemen's upheaval has emboldened Al Qaida militants to challenge authorities in the country's nearly lawless south.