A car bomb Tuesday destroyed parts of the French Embassy in Tripoli. The building was mostly empty in the morning attack, however.
Interim Italian Foreign Minister Mario Monti said NATO foreign ministers in Brussels were discussing Libyan military training at the time of the attack.
The Tripoli attack "shows that it is necessary to multiply efforts to support the democratic transition and isolate extremists," Monti said.
Italian representatives at a Libyan security meeting in Paris this year said they were helping the Libyan government with border security but stressed assistance was a global matter.
The U.N. Security Council issued a statement saying attacks on diplomatic interests could "seriously impede" the work of the international community in Libya.
An attack on the U.S. consulate in Benghazi, Libya, last year resulted in the death of U.S. Ambassador Chris Stevens and three members of his staff.
A statement from the British government on Tuesday's attack warned of reprisals because of the French intervention in Mali. Mali's government in January asked for French support to help take on al-Qaida and foreign rebels.
There were no claims of responsibility for Tuesday's attack.