Libyan state-run media said gunmen in the town of Sirte have taken over several government buildings, including radio and TV stations.
Details remained unclear, but the Libyan state news agency said armed men stormed several buildings in the coastal town Friday and Saturday and continued to occupy them.
It was not clear with whom the gunmen were affiliated, although the Libya Herald newspaper reported that they were Islamic State fighters.
Also Saturday, a bomb exploded at an oil pipeline from Libya's El Sarir field, halting flows to the port of Hariga. No group claimed responsibility, but Hariga oil terminal supervisor Rajab Abdulrasoul told Reuters that "what happened is sabotage.''
Oil infrastructure, ports and pipelines in the North African OPEC member state are often targets of attack.
A spokesman for the National Oil Corp. said a tanker had been loading up with crude at Hariga. He said it could take up to three days to restore the pipeline.
Hariga had just reopened after a strike by guards there. The country's two main oil ports and nearby fields are still closed after clashes between rival armed groups trying to gain control of them.
Earlier in the week, a U.N. report said that Libya is beset by turmoil, lawlessness and armed conflict. It painted a bleak picture of a society run by several armed factions.
Report authors said Libya is facing the worst political crisis and escalation of violence since the 2011 armed conflict that toppled long-reigning dictator Moammar Gadhafi.
While two competing parliaments and governments claim legitimacy and the right to rule Libya, the report said powerful armed groups exercise control, committing human rights violations with impunity.
Some information for this report came from Reuters.