The explosion took place just before Friday prayers at the Saad Ibn Ibada mosque located between Benghazi's al-Majouri and Berka districts, said Motaz Agouri, an official from Benghazi security directorate's media office.
The explosion rattled near a mosque in the Libyan city of Benghazi, leaving eight people dead, city residents told Sputnik. The devices appear to have been activated remotely using a mobile phone, one military source said.
No group immediately claimed responsibility for the attack.
"This heinous act should not provide a justification for revenge attacks".More news: Georgia toddler with Down syndrome named 2018 Gerber baby
In January, a twin auto bombing near a mosque in Benghazi's Salmani neighborhood killed at least 33 people.
"Direct or indiscriminate attacks against civilians are prohibited under global humanitarian law and constitute war crimes", the mission added, calling for "prompt, impartial investigations to bring perpetrators to justice".
Libya has been plagued by unrest and political division since the uprising that toppled its former leader Muammar Gaddafi's regime in 2011. The LNA has been battling Islamists, including some linked to Daesh and al-Qaeda.
Fears over potential reprisals are heightened by the reported summary execution of around 10 jihadist prisoners by a commander loyal to Haftar following last month's bombings.More news: Joaquin Phoenix to play The Joker
Mr al-Werfalli is wanted by the ICC for allegedly carrying out a number of similar killings.
The UN-backed unity government based in the capital has struggled to assert its authority outside western Libya.
The UN has been trying to mediate for years, hoping elections could help stabilise Libya.
The North African nation has had competing governments aligned with rival military factions based in Tripoli and the east since 2014.More news: 'He's achieved a terrific job': Matt Patricia retains Jim Bob Cooter