An election official in Derna said the bombs were believed to have been remotely detonated, the Libya Herald reported.
"The blasts caused serious damage to the buildings," all schools, the election official said.
The bombings also frightened voters into possibly staying home rather than vote at the remaining 13 polling centers, the official said.
The Derna Local Council expressed concern about whether elections to the Constitutional Committee could be conducted because of a lack of security, but on Monday a council member told the Herald the elections would proceed. People wanted to vote and had volunteered to protect the polling stations, the official said.