This was the first group of 320 alleged Islamic State [I.S.] jihadists to be tried and sentenced.
Thirteen other accused were sentenced to life in prison, after the trial that began last August in the western city of Misrata, the AFP journalists said.
The accused were Palestinian, Sudanese and Libyan. All had been in custody since December 2016 and were convicted of joining a terrorist group, as well as murder.
Some others were acquitted but exactly how many was not clear.
In addition, the court sentenced three minors to 10 years in prison each, said lawyer Lotfi Mohaychem, who represented families of anti-I.S. fighters killed in the battle for Sirte.
The suspects appeared in the dock clad in blue prison overalls, bearded and with shaven heads.
Relatives of those killed in the Sirte battle filled the packed the courtroom.
"As lawyers for the victims' families we see the verdict of the court as very satisfying and very just," Mohaychem said. "The court sentenced those whose guilt was demonstrated and acquitted those against whom there was insufficient evidence."
When the verdicts were read, cries of joy and applause filled the room along with shouts of, "God is greatest" and, "The blood of the martyrs has not been spilled in vain!"
Mostafa Salem Trabelsi, who described himself as the uncle of one of the victims and father of another who is disappeared, said he felt "relieved despite the pain."
Libya was plunged into more than a decade of chaos and lawlessness following the 2011 NATO-backed uprising that led to the removal and killing of longtime dictator Kadhafi.
Dozens of militias and jihadist groups took advantage of the power vacuum, with I.S. setting up base in Sirte and the eastern town of Derna before being driven out with the help of U.S.-led air strikes.
I.S. had captured the central coast city of Sirte in 2015, setting up a stronghold before being driven out the following year by forces loyal to the Tripoli-based Government of National Accord in power at the time.
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