Gunmen have killed a retired police colonel and two sons of other retired high-ranking security officials, the latest in a series of assassinations in Libya, health officials said.

Fadia Al Burghthi, a hospital spokeswoman, said Abdel Fatah Al Barasi died after being shot in the head while in his car yesterday in the eastern city of Benghazi.

Salah Abd Al Razak and Zakaria Abdullah Al Darsi, both sons of colonels, were also shot and killed in the street by assailants yesterday.

Libya has been plagued by assassinations and abductions of security officials blamed largely on militias that emerged during the country's 2012 civil war.

On Thursday, clashes between soldiers and a powerful militia erupted in Benghazi after the abduction of a military commander's son.