Speaking at the ceremony, held in Beirut on Friday, Moussa voiced Lebanon’s solidarity with the Iranian government and the families of the kidnapped diplomats.
The Lebanese parliamentarian further called on the international community to help clarify the fate of the abductees.
The Iranian Embassy in Beirut also urged the Lebanese government to seriously pursue the case of the kidnapped diplomats.
On July 4, 1982, the four Iranian diplomats were kidnapped by a group of Israeli-backed gunmen at an inspection post in northern Lebanon.
In September 2008, the Lebanese government sent a letter to the then UN secretary general, Ban Ki-moon, in which Beirut confirmed the abduction of the Iranian diplomats in the Lebanese territory and called for UN action to pursue the case.
Israel has claimed that the Iranian diplomats were abducted by a Lebanese militant group and killed shortly after their abduction.
The Lebanese resistance movement Hezbollah has, however, said that it has evidence that they are still alive and in Israeli captivity.