A car bomb explosion in the eastern Libyan city of Benghazi killed two United Nations' staff on Saturday, several medical sources said.
The UN is trying to broker a truce in the capital Tripoli, where the eastern-based Libyan National Army (LNA) launched a surprise attack in April.
A Reuters reporter at a Benghazi hospital where casualties of the blast were taken saw a list of names of those killed identifying them as part of the United Nations Libya mission (UNSMIL).
Several medical and security officials at the hospital said two UN staff, one of them foreign, had been killed.
UNSMIL spokesman Jean El Alam said via email that the organisation was "in the process of gathering information".
The explosion happened in front of a shopping mall and bank. At least one burned out UN car could be seen at the scene.
The LNA has yet to advance beyond the southern suburbs of Tripoli, which is home to the internationally recognised government.
Around the time of the blast, LNA commander Khalifa Haftar, announced a halt to military operations during the Muslim Eid al-Adha holiday, which lasts from Saturday until Tuesday, according to a statement from his forces in Benghazi.
On Friday, the government in Tripoli said it had accepted a UN proposal for a ceasefire during the holiday period.
However, it was not clear whether fighting in the capital would actually cease. More than 105,000 people have been displaced during the clashes, according to the United Nations.
UNSMIL will be responsible for monitoring any violations, the Tripoli government said.