A Libyan police officer was killed and another wounded in fresh attacks in Benghazi, in another sign of mounting violence in the eastern city, a security official told AFP news agency.
"Unknown shooters gunned down a police officer and seriously wounded another during two separate attacks Wednesday evening in Benghazi," said Lieutenant-Colonel Ibrahim al-Charaa, spokesman for the city's security forces.
"The murderers ... fled the scene after firing off a hail of bullets," he said explaining that the victim died of his wounds upon arriving at hospital.
In the other attack, he said the gunmen fired on a police officer who suffered a gunshot wound to the head, leaving him in critical condition.
Benghazi, the seat of the 2011 uprising that toppled Muammar Gaddafi, has been caught in spiralling violence since his fall.
Fighters in the city have targeted judges, members of the security forces, local government officials and journalists in recent months.
Meanwhile, tribal leaders will hold more talks on reopening several seized oil export ports in eastern Libya but the government will not negotiate with protesters blocking the ports, Prime Minister Ali Zeidan said on Wednesday.
Armed protesters have refused to lift a blockade of vital oil terminals in eastern Libya, despite a tribal pledge to do so, sending output plummeting to 250,000 barrels per day from the normal level of almost 1.5 million bpd.
"We prefer to give an opportunity to these initiatives, which will be the last," said Zeidan.
The Libyan leader warned his government would "take its responsibility" if the mediation failed, while saying the crisis would be ended in January.
At the weekend, Zeidan issued a renewed threat of force to lift the blockade - an action that the armed security guards launched in July in a protest to support demands for regional autonomy.
However, on Wednesday he refused to negotiate with the protesters, accusing them of "betraying the mission they were entrusted with to secure these oil sites".