A round of gunfire struck a helicopter transporting electoral material for Libya's vote on Friday, killing an election commission worker, officials said.
"A helicopter carrying ballots and flying over the region of Hawari [south of Benghazi] was struck by small arms fire," army spokesperson Colonel Ali al-Sheikhi said. "One person on board was killed."
The helicopter, he added, made a safe landing at Benina International Airport, which serves the eastern city of Benghazi.
An official of Libya's electoral commission said a colleague was killed in the incident.
Also on Friday, the eve of elections, two rockets hit Benghazi Medical Centre, without causing casualties or material damage, according to an official at the hospital, Ala Ben al-Kazza.
The motive of the attack was unclear but Benghazi residents speculated that electoral material was being stocked in the premises.
The violence comes ahead of Saturday's landmark elections for a national assembly, the first democratic poll after more than four decades of dictatorship under Moammar Qaddafi, who was toppled and killed last year.
East Libya is the heartland of several groups threatening to sabotage the elections unless the country's interim rulers review the allocation of seats in the General National Congress.
The current system allocates 100 seats to the West, 60 to the East and 40 to the South. Advocates of federalism are demanding an equal distribution of seats between Libya's regions.