Benghazi, Libya: Seven jihadists of the Islamic State group and three soldiers of Libya's recognised government died in weekend clashes in the eastern city of Benghazi, military and medical sources said Sunday.

A source at the city's Al-Jalaa hospital, quoted by Libya's government-run news agency, said three soldiers were killed and 21 colleagues wounded during the Saturday-Sunday clashes in the Saberi district of central Benghazi.

Seven members of Libyan branches of IS were killed and seven others captured, according to the army's central command.

Controversial army chief Khalifa Haftar announced a military offensive on September 19 against anti-government forces in Benghazi, 1,000 kilometres (600 miles) east of the capital Tripoli.

Libya has been sliding deeper into turmoil since the 2011 ouster of its longtime dictator Moamer Kadhafi, with two rival administrations and militias battling for control.

An internationally recognised parliament is based in Tobruk in the country's far east while its rival operates from Tripoli, backed by the Islamist-backed Fajr Libya (Libya Dawn) militia coalition.