Clashes erupted between the Libyan self-styled army and Derna Shura Council in Fatayeh district in the east of the city.
The fighting started Monday morning as Khalifa Haftar-commanded forces, which are encircling Derna, arrived on the outskirts of Fatayeh university.
Later in the day, the forces withdrew as heavy artillery fire thwarted their advance.
Seven fighters from Haftar's forces have been reported killed and 15 others injured in Fatayeh frontline, sources said.
Meanwhile, the spokesman for the Derna Shura Council, Mohammed Al-Mansouri, told reporters that one of their fighters was killed in today's clashes, adding that Haftar's forces pulled out to Martuba district - just outside Derna.
Haftar announced Monday in a speech celebrating the fifth anniversary of Dignity Operation in Benghazi, the "zero hour" to "liberate Derna" even if "we have to evacuate all civilians from it."
Derna has been besieged by Haftar-led Al-Mukhtar Operations Room for a long time with the grip toughened last August disallowing the resident to receive enough humanitarian assistance since.