Video shows Libya army 'executions'

"Al Jazeera has received pictures that purportedly show Libyan army officers killed for refusing to fire on the rebels.

It is claimed the soldiers refused to shoot rebels in the mountainous region west of Tripoli. The pictures were sent to Al Jazeera by a rebel group in the area.

A survivor of the killings says the men were rounded-up, their legs tied before being shot in the head or back from close range.

The pictures emerged as rebel fighters face perhaps their greatest challenge yet as they take stock of what seems a slowing of momentum in their campaign."