Headstones on World War II military graves in Libya's eastern city of Benghazi have again been desecrated in the second such attack in four months, local officials said on Saturday.

"On Thursday, Christian graves were desecrated for a second time in Benghazi," Mohammed al-Quzairi of the local security committee said, adding that the identity of the assailants was unclear.

The Benghazi civilian council said it was trying to track down those responsible.

"We are cooperating with the security committee to ascertain the identity of the assailants and bring them to justice as quickly as possible," its spokesman, Khaled al-Jazawi, said.

A similar attack hit the same military cemetery in February.