Libyan National Oil Corporation (NOC) Chairman Mustafa Sanalla on Wednesday rejected Prime Minister Abdulhamid al-Dbeibah's authority to sack him, raising the prospect of an open struggle for control of the state energy producer.

In a furious televised speech, Sanalla said the prime minister's mandate to govern had expired, and warned him not to touch NOC.

Three witnesses claimed that an armed force was deployed outside the NOC building later in the day, with one asserting that it was aligned with al-Dbeibah.

A spokesperson for the al-Dbeibah-led Government of National Unity was not immediately available for comment.