Fierce fighting between the Libyan army and fighters belonging to armed groups in the city of Benghazi has killed at least 13 people, residents have said.

Residents also said on Monday that warplanes and tanks were being used in the fighting near Benghazi's port, an important conduit for food and fuel supplies to the eastern part of the country.

Reuters news agency reported smoke rising from the port which warplanes could be heard firing into, hitting a ship. 

The battle is part of a wider conflict in the North African state where former rebels who helped oust the former leader Muammar Gaddafi in 2011, are fighting for power and a share of Libya's large oil revenues.

Army special forces, backed by forces loyal to a former general, launched an offensive in the Benghazi area two weeks ago against al-Qaeda-linked fighters.

Meanwhile, Red Crescent medics said that they evacuated 53 foreign workers and 14 sick people trapped inside a hospital next to the port while the army moved more tanks and artillery into the city.

At least 243 people have been killed since the army started the offensive, medics said.

Dozens of residents were leaving the fighting in Libya's second city, heeding a call by the army to evacuate the port area and main commercial district.

Libya is currently split between rival tribes and political factions with two governments vying for legitimacy since an armed group from the western city of Misrata seized the capital city of Tripoli in August, forcing Prime Minister Abdullah al-Thinni to relocate to the east.

Forces of ex-general Khalifa Haftar, which back the army in Benghazi, have planes from the Gaddafi-era air force.

Source: Reuters