At least 16 prisoners, including members of al Qaeda, escaped from a prison in the southern Yemeni city of Aden Monday, Yemeni officials said.
A prison officer said at least 10 convicts escaped through an up to 130 feet (40 meter) long tunnel, which took the inmates from under the western side of the Aden prison to near a petrol station outside the prison walls.
A security official said 15 militants fled in the prison break, including 12 convicted for the killing of security officials and a bank heist.
The discrepancy in the number of escaped prisoners could not be immediately reconciled. Both officials spoke on condition of anonymity because they were not authorized to speak to the media.
It was the second major jailbreak involving al Qaeda members since June, when dozens of al Qaeda militants escaped from a jail in another city, Mukalla.
Al Qaeda members, including one convicted in a 2002 attack on the French-flagged oil tanker Limburg off Yemen, escaped from a jail in the capital Sanaa in 2006, helping to revive the group after Saudi security forces weakened it in that country.