Story highlights

NEW: Security forces close down all roads leading to Aden after the escape

The 15 who escaped are suspected members of al Qaeda in the Arabian Peninsula

Security officials: The escapees dug a 6-meter tunnel

Earlier this year, a dozen suspected al-Qaeda prisoners escaped, killing four guards

(CNN) —  

Fifteen suspected members of al Qaeda in the Arabian Peninsula escaped from a south Yemen prison Monday morning, security officials said.

The escapees dug a 6-meter tunnel in the western section of the Central Security prison in Aden, the security officials said.

The escapees encountered no government resistance, the security officials said.

Security forces closed down all roads leading to Aden and created checkpoints on every main street after the escape.

Witnesses said tanks were deployed, and hundreds of additional troops were stationed in front of security offices and government buildings.

Some residents in Aden complained that security forces on roads and checkpoints were using excessive force with civilians.

“The forces were treating us as if we are criminals, at times making threats to anyone who asks them questions,” said Khaled Mansoor, a bus driver in Aden.

Aden, the business capital of Yemen, has been under a terror threat since May, when suspected militants took over neighboring Abyan province and announced it an Islamic emirate.

Earlier this year, at least a dozen suspected al-Qaeda prisoners escaped from a political security prison in Aden, killing four guards in the process.