Libya's prosecutor general has ordered the arrest of eight officials as part of his inquiry into the recent flood disaster that killed thousands, his office said Monday.

The flash flood, which witnesses likened to a tsunami, broke through two aging dams on September 10 after a hurricane-strength storm lashed the area around Derna, a port city in Libya's east.

The officials are suspected of "bad management" and negligence, among other offenses, a statement from the prosecutor general's office said, adding that seven of them served currently or previously in offices responsible for water resources and dam management.

"The mistakes that they made" and their "negligence in the matter of disaster prevention" contributed to the catastrophe, the statement charged.

Derna's mayor Abdulmonem al-Ghaithi, sacked after the flood, is among the detainees.

According to the latest toll announced by the authorities in the east of the country on Monday, at least 3,875 people died in the disaster.

International aid groups have said 10,000 or more people may be missing.

After opening a probe, Libya's prosecutor general Al-Seddik al-Sour said more than a week ago that the two dams upstream from Derna had been cracked since 1998.