The state-run Libyan Post Telecommunications Company said it was trying to determine whether digging for bodies had severed fibre optic cables, or whether it was an act of sabotage, company spokesman Mohamed Al Bdairi said.
Attempts to find survivors from the September 11 disaster have all but ended, with almost all of the estimated 4,000 to 15,000 victims thought to have died in the moments after two dams in the mountains above the city collapsed.
On Thursday, the International Organisation for Migration (IOM) said at least 43,059 people have been displaced by severe floods in north-eastern Libya. The organisation said a lack of clean water supplies appeared to be driving many displaced people out of Derna to municipalities to the east and west of the Mediterranean city.
Anger has risen after a series of experts and local officials said the dams had not been maintained since 1998, while cracks in the structures had been identified.
When communications were interrupted on Tuesday, there was speculation that authorities had cut internet and phone lines to stem growing protests.
The communications problem has slowed recovery efforts in the city, which has been segmented by authorities in an attempt to stop the spread of waterborne disease.
Health authorities have launched a vaccination campaign that initially targeted search and rescue teams and children in Derna and other impacted areas.
Hundreds of angry protesters gathered outside the main mosque in Derna on Monday. They lashed out at the political class that has controlled Libya since the removal and killing of Muammar Qaddafi in a Nato-supported 2011 uprising.
The protesters demanded an investigation into the disaster to be accelerated and called for the reconstruction of Derna to be under UN supervision.
General prosecutor Al Sidiq Al Sour has launched an investigation into the collapse of the two dams in Derna. In comments to local TV on Wednesday, he vowed to take “serious measures” to deliver justice for the victims of the floods.
“It’s a great catastrophe, and the casualty toll is significant. Certainly, if measures had been taken at the right time in the past years, a catastrophe with such magnitude wouldn’t happen,” he said.