The northern and southern armies each had around 30 Russian-made surface-to-surface missiles before the war broke out, according to Western military sources in the region.
The two Russian-made missiles barely missed the Boeing 757.
The incident near the international airport at Mombasa came six months after a similar Russian-made missile was fired at an American military plane in Saudi Arabia.
Federal investigators arrested a British citizen in Newark last week and accused him and two other men in a plot to sell Russian-made shoulder-fired missiles to terrorists.
Assault rifles, grenade launchers, antitank weapons and Russian-made surface-to-air missiles have, for example, been purchased in Cambodia.
The British soldiers have been particularly focused on finding the locations of Colonel Qaddafi's Russian-made surface-to-air missiles.
Minutes earlier and some 20 miles away, terrorists fired shoulder-launched Russian-made missiles at an Israeli airliner but missed.
They report that a "potent stash" of Russian-made surface-to-air missiles is missing.
They said the plan is likely to include an offer to buy Russian-made missiles that could be used in a defensive shield over Russia and Europe.
The Sakar-20 is a Russian-made 122mm surface-to-surface missile.