The prosecutor's office said the five, detained on suspicion of illegal goods transit, were transporting the parts, declared as legal items, to a customs warehouse in Tallin, the Estonian capital, without official permission.
The prosecutor heading the investigation said, "The movement of such goods is strictly monitored throughout the world, and their transit without the necessary authorization can pose an explicit danger on an international scale."
The prosecutor's office said the parts were mainly of Russian and Belarusian origin, and were intended for export to China, Malaysia, and Bangladesh.
The items are on an official government list of strategic military goods that may not be transported without special permission from the Estonian Foreign Ministry.
