Two employees of the National Oil Corporation and two attackers reported dead after several blasts heard in Tripoli
An assault on the headquarters of Libya's state oil firm, the National Oil Corporation (NOC), has left two security guards and two attackers dead, according to a security official.
Monday's attack on the landmark building in Tripoli, the nation's capital, comes just a week after the UN negotiated a truce between rival factions fighting for greater control of the capital.
Forces linked to the Tripoli government published pictures of a human leg, which it said belonged to one of the gunmen who had blown himself up.
Libya's health ministry said that in addition to the deaths, 10 people had been wounded.
"The death toll so far is two killed from NOC staff and two attackers," said Ahmad Ben Salim, spokesman for the Special Deterrence Force (Rada), a militia that operates as Tripoli's police force, which had surrounded the NOC building.
Ben Salem said "the situation is under control" and that the remains of two "suicide bombers" were found inside the building.
They were discovered on the second and third floors, he said, while identifying the two people killed in the assault as security guards.
Tripoli security chief Salah al-Semoui blamed the Islamic State group for the attack, although there was no immediate claim of responsibility.
Fighters loyal to the Islamic State group have previously carried out attacks in Tripoli and other Libyan towns and cities.
The UN Support Mission in Libya denounced a "cowardly terrorist attack," calling it in a statement a "blow against Libyans everywhere".
Ben Salem was not able to provide details on the identity of the attackers but the Special Deterrence Force also labelled the incident a "terrorist" attack.
NOC chairman Mustafa Sanallah, who was safely evacuated from the headquarters, told the news channel Libya 218 that staff members had been killed and others wounded, some of whom were in a "serious condition".
Several armed men were reported to have attacked the headquarters on Monday morning, with a series of blasts heard before ambulances carried wounded people away, a Reuters witness said.
"Three or five gunmen were shooting inside the building," an NOC staff member earlier told the Reuters news agency after he said he had jumped out of a window to escape. "Several people were shot."
The NOC building is covered mainly in glass, and a witness said several people had been wounded by shattered windows.
Firefighters and onlookers gather in front of the headquarters of Libya's National Oil Company in the capital Tripoli on September 10, 2018 (Mahmud Turkia / AFP)
Security forces were smashing windows so staff could escape, witnesses said.
Libya has been divided between rival governments and military factions based in the east and west of the country since 2014, causing political deadlock and an economic crisis.
However, the NOC has continued to function relatively normally across Libya, which relies on oil exports for most of its income.
Oil production has been hit by attacks on oil facilities and blockades, though last year it partially recovered to around one million barrels per day.