TRIPOLI, Libya — Libya’s long-delayed efforts to prepare a new charter hit another obstacle on Thursday when elections for a 60-member constitutional drafting committee fell well short of expectations, with a low turnout and 13 of 60 constituencies failing to elect candidates by the end of the day.

Election officials blamed widespread disillusionment with the electoral process caused by political bickering between elected members of the General National Congress. But the muted turnout was also a reflection of Libya’s deteriorating security and growing internal tensions two and a half years after the overthrow of Col. Muammar el-Qaddafi.

Unlike the general elections in 2012, when Libyans turned out with enthusiasm for their first chance to vote in an election after 42 years of dictatorship, there were more officials and observers than voters on Thursday in some polling stations in the capital around midmorning. Attendance was not helped by lashing rain along the coastal towns in the afternoon. By evening, just short of 500,000 people had voted, less than half of those registered and barely a sixth of the national electorate.

Violence was of far greater concern, however, since the drafting of the constitution may not be able to go ahead without sufficient representatives.