Islamic State bombers on Sunday mounted three suicide attacks against Libyan government forces in an attempt to halt their advance inside the extremist militia's stronghold in the coastal city of Sirte, a pro-government media centre said.
The attacks were carried out using car bombs against the positions of the government forces in different parts of Sirte, the centre covering the military operation in the central city said.
One car bomb exploded near a field hospital in Sirte's western district of al-Khamseen.
No casualties were reported.
Last month, forces loyal to the UN-backed unity government, began an onslaught to drive Islamic State from Sirte, which the radical group captured last year.
In the past few days, the forces, mainly from the western city of Misrata, made major territorial gains around and inside Sirte, the biggest city held by Islamic State outside Iraq and Syria.
On Friday, the government forces seized Sirte's port, located around 5 kilometres east of the centre of the city.
Sirte, around 450 kilometres east of the capital Tripoli, is strategically important because it links Libya's east and west.
Libya has been in turmoil since the 2011 revolt which toppled long-time dictator Moamer Gaddafi.
Islamic State has taken advantage of the chaos to seize territory along the sparsely populated central coast and expand in the oil-rich country.