Greek police have arrested three Iraqi Kurds with British passports in the eastern border town of Alexandroupoli suspected of trying to move weapons towards the Middle East, state-run radio reported on Sunday.
Along with the men, police found a large number of weapons and ammunition in two camper vans, according to local media.
One camper found near the city's port contained 20,000 cartridges and 18 weapons.
The other camper searched by authorities at a nearby Greek-Turkish border crossing contained 200,000 cartridges and four weapons.
"Several firearms and substantial ammunition have been found," a police officer told dpa, without providing further details on the find.
It is the second such arrest in the area in the past two weeks.
At the end of January, Greek police arrested two suspected jihadists at the Turkish border.
Interpol and British authorities have also been informed about the case.