Six members of Libya's security forces were killed, apparently "executed," after clashes in Benghazi pitting protesters against a defence ministry brigade, a Libyan medical examiner told AFP Saturday.

"From the nature of the wounds it is clear that the six were executed," the medical examiner said on condition of anonymity, adding that four of them were shot in the head while the others were shot in the chest as well as the head.

An official at the prosecutor's office confirmed the toll.