A suicide bomber targeted the entrance of Libya's Foreign Ministry in Tripoli on Tuesday, 25 December killing three people, including a prominent militia leader, according to security officials.
The 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, located at the heart of Tripoli.
They identified the militia leader killed in the attack as Abdul-Rahman Mazoughi of the Revolutionary Brigade.
The officials spoke on condition of anonymity because they were not authorized to brief the media.
The Health Ministry confirmed the death toll and said 10 other people were wounded.
No one immediately claimed the attack, which bore the hallmarks of the Islamic State group. The United Nations in Libya condemned the "cowardly terrorist" attack on the Foreign Ministry.
"Terrorism will not triumph over the Libyans' decision to move forward toward building their state and renouncing violence," it said in a statement.
"We will work with the Libyan people to prevent terrorist groups from turning Libya into a haven or an arena for their crimes," said Ghassan Salamé, the UN special envoy to Libya.
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.