A Libyan security official says gunmen have killed a senior police officer in the hometown of former dictator Moammar Gadhafi.

The official says Col. Ramadan al-Turouk was shot dead on Monday night in his car, close to his home in Sirte. Al-Turouk was head of the local passport and immigration office.

The official spoke on condition of anonymity according to regulations. He says it was not known who the attackers were and that an investigation is underway.

There has been a spike in targeted killings in Libya since Gadhafi's ouster in 2011. An American teacher was killed last week in the restive eastern city of Benghazi.

Authorities blame the killings on militias resisting state authority and Islamists seeking revenge on Gadhafi-era officials.