"The safety of peacekeeping troops must be the top priority. All parties to the conflict are urged to respect international humanitarian law and ensure the security of peacekeeping personnel," defence ministry spokesman Rico Ricardo Sirait said in a statement.

The UN Interim Force in Lebanon (UNIFIL) said two of its personnel were killed Monday in an explosion and another died late Sunday when a projectile hit their position.

The UN force said it launched an investigation into the separate incidents.

Condemning the "heinous" attacks, Indonesian Foreign Minister Sugiono said on Tuesday that he had discussed the deaths with UN chief Antonio Guterres, and asked for an emergency UN Security meeting as well as "a swift, thorough and transparent investigation".

"The safety and security of UN peacekeepers is non-negotiable and must be upheld at all times," said Sugiono, who like many Indonesians goes by only one name.

Jean-Pierre Lacroix, UN under-secretary-general for peace operations, condemned "these unacceptable incidents and said "all acts that endanger the peacekeepers must stop".

Permanent Security Council member France has said it was seeking a meeting of the body over the matter.