A car bomb explosion in Benghazi killed three UN staff members and two other mission members, the United Nations said.
The attack came as the United Nations was brokering a truce in Tripoli, where the eastern-based Libyan National Army (LNA) force launched a surprise attack in April, part of the chaos in Libya since the toppling of Muammar Gaddafi in 2011.
UN Secretary-General Antonio Guterres condemned the attack, a spokesman said in a statement.
“The UN does not intend to evacuate from Libya,” the assistant secretary-general for peace operations, Bintou Keita, told the Security Council, which also condemned the attack.
The United Nations gave no more details, saying some casualties were members working in Benghazi, where its Libya mission recently boosted its presence.
LNA spokesman Ahmed Mismari told reporters two of those killed were guards with UNSMIL. He added 10 people were wounded, including children.
The explosion happened in front of a shopping mall. At least one burned-out UN car could be seen.
The LNA has yet to advance beyond the southern suburbs of Tripoli, home to the internationally recognised government.
Around the time of the blast, LNA commander Khalifa Haftar announced a halt to military operations for 48 hours during the Muslim Eid al-Adha holiday according to a statement from his forces in Benghazi.