The U.S. Congressional Research Service (CRS) says that last year, three ships heading for Iran were halted at sea or at port on suspicions of carrying North Korean-made weapons.

The service said that Western and Israeli intelligence authorities believe that the weapons were to be delivered to Hamas and Hezbollah extremists.

In July last year, a ship was halted after it was found to be carrying North Korean-made weapons.

The other suspected detentions of ships carrying North Korean weapons have not been made public.

According to the CRS, Western countries have concluded that Hezbollah was to be the final recipient of the North Korean weapons aboard a Georgian-flagged cargo plane that was detained by Thai authorities in December.