Libya's official news agency says the son of the country's defense minister has been set free after kidnappers held him for four months.

The agency quoted Saleh Gawida, head of the National Security Committee in the interim parliament, on Monday as saying that Mohammed Abduallah al-Theni was released but gave no further details.

Al-Theni, 26, was abducted by unknown assailants last September in Tripoli. Many linked his kidnapping to his father's remarks against unruly militias, which have been blamed for a series of killings, abductions and torture.

Since the end of its 2011 uprising, Libya's central government has virtually collapsed and it lacks an efficient police and military. Rebel forces and militias quickly filled the security vacuum left after the downfall of Moammar Gadhafi.