At least 18 people were killed during clashes between Major General Khalifa Haftar's forces and Islamic militias in Libya's Benghazi city, taking toll to 52.
In the past two days, at least 34 people were killed in an attack launched by Haftar's forces, Xinhua reported.
However, Friday's clashes were even more violent as they took place in a densely populated area.
According to eyewitnesses, clashes continued all day and residents were stuck and unable to flee.
Helicopters launched air raids on Laithi, Boatni and Al-Masakin areas, which are located in the south-east region of the city.
Several explosions were also heard in different parts of the city.
Haftar, who played a major role in toppling Libya's former leader Muammar Gaddafi, has been waging a war on Benghazi's Islamist armed groups since May.
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However, Haftar's secular-leaning forces recently met several major setbacks and have lost most of their bases in Benghazi.
His troops now only control Benghazi's Beinina Airport and its surrounding areas.
Libya has witnessed a drastic escalation of violence after the 2011 turmoil that ousted and killed Gaddafi.
The Islamic militants and pro-secular militia have been vying for cities and towns for months and fighting continues in the cities of Tripoli, Benghazi and Gharyan.