The attack underscored the fragility of the latest peace push in the North African nation, which has been beset by turmoil since 2011.
Former French president Nicolas Sarkozy will face trial over charges he misused his influence to secure leaked details of an inquiry into alleged irregularities in his 2007 election campaign, a source said on Thursday.
Sarkozy, 63, was taken into police custody early on Tuesday and was being questioned by officers specialising in corruption, money laundering and tax evasion at their office in the western Parisian suburb of Nanterre.
Libya's UN-backed Prime Minister Fayez al-Sarraj holds French-brokered talks on Tuesday with Khalifa Haftar, the rival military commander who controls the east, to try to end the chaos in the conflict-ridden country.
At least 47 people were killed on Thursday when Libya's worst bomb attack since the fall of Muammar Gaddafi hit a police training centre as hundreds of recruits gathered for a morning meeting.