A car bombing at a checkpoint in the Libyan oil port of Ras Lanuf left seven people dead and 11 wounded on Thursday, a Petroleum Facilities Guard spokesman said.
Ali al-Hassi said the car had been in a queue at the checkpoint and exploded when it reached the front. The casualties included guards and civilians, he said.
Ras Lanuf and the nearby oil port of Es Sider have come under attack from Islamic State militants this week.
Fires have spread to seven oil tanks at Ras Lanuf and Es Sider following the attacks, said al-Hassi. Five storage tanks are burning at Es Sider and two at Ras Lanuf.
Two tanks were hit by shelling this week and the fires have since spread.
Hassi said the PFG remained in control of the area and that there were no clashes on Thursday.
Separately, however, at least 65 people were killed on Thursday when a truck bomb exploded at a police training center in the town of Zliten east of Tripoli, local officials and hospital sources said.
Both Es Sider and Ras Lanuf have been closed since December 2014. They lie between the city of Sirte, which is controlled by Islamic State, and the eastern city of Benghazi.
An oil official based in eastern Libya estimated that the tanks hold up to 460,000 barrels each.
Libya is split between political factions and armed groups competing for power and for the country's oil wealth, five years after the revolt that toppled Libyan leader Muammar Gaddafi.
The OPEC member state's oil output has plunged to less than one quarter of a 2011 high of 1.6 million barrels per day.