A suicide bomber targeted the entrance of Libya's Foreign Ministry in Tripoli yesterday, killing three people, including a prominent militia leader.
Officials said a second attacker was shot dead by guards before he could detonate his explosive vest.
An explosion believed to have been caused by a car bomb went off before the two attackers approached the ministry. They identified the militia leader killed in the attack as Abdul-Rahman Mazoughi of the Revolutionary Brigade.
The Health Ministry confirmed the death toll and said 10 others were wounded.
No one immediately claimed the attack, which bore the hallmarks of Isil.
Libya has been a haven for militants since a 2011 uprising toppled dictator Moammar Gadhafi. The country is split between rival governments, each backed by an array of local militias.