Slovenian police started fining Croatians on January 26.
Croatia has "no legal grounds whatsoever" for the move.
“Slovenia will insist on arbitration implementation”
Juncker says it concerns the whole EU.
But face heavy fines for doing so.
Prime Minister Miro Cerar set out the priorities of Slovenian foreign policy in his address to Slovenian diplomats at Brdo pri Kranju on Friday, asserting the country's intention to consistently insist on the implementation of the border arbitration award.