Armed men killed the head of security on Thursday in the Islamist-held coastal city of Sirte, hometown of slain dictator Muammar al-Gaddafi, a security source said.
Colonel Senussi Kaiba was killed along with his driver when armed men opened fire at their car in a residential area of the city, the source added.
Two days earlier, a local administration official escaped uninjured after armed individuals opened fire at him in a similar attack.
Sirte is in the hands of Islamist militias, including Ansar al-Sharia, which the UN added to its terror list in November over links to al-Qaeda and for running camps for the Islamic State of Iraq and Syria (ISIS) jihadist group.
The Fajr Libya (Libya Dawn) alliance of Islamist-backed militias is also present in the city, which lies 500 kilometers (310 miles) east of Tripoli.
Although Fajr Libya had not taken part in the first round of peace talks in Geneva last week, they have declared a ceasefire in light of the agreement on a roadmap to form a unity government.
The Islamic State of Iraq and Syria (ISIS) militant group is also thought to have gained a foothold in eastern Libya, and recently claimed to have executed two Tunisian journalists there.
Jihadists are reported to have set up camps in Libya, including in the remote southern desert, to train militants to fight in Mali, Iraq or Syria
Almost four years after a NATO-backed war ended Gaddafi's one-man rule in 2011, Libya is struggling with instability as two rival administrations compete for power and warring armed factions skirmish for control of territory, especially oil sites, across the North African state.
Western powers, who backed the military uprising against Gaddafi, fear that extremists, who they armed and trained during the uprising, are seeking to exploit a power vacuum in the oil-producing nation.
The conflict has driven at least 120,000 people from their homes and caused a humanitarian crisis, said a joint report by the UN human rights office and UN Support Mission in Libya (UNSMIL) that also documents shelling of civilian areas.
© Al-Akhbar. All rights reserved