Speaking in Brussels, the commissioner made a reference to the "constructive" meeting on Saturday between European Commission President Jean-Claude Juncker and Slovenian and Croatian prime ministers, Miro Cerar and Andrej Plenković.

On the occasion, the Commission presented detailed guidelines for the implementation of the EU-decreed systematic checks on the Slovenian-Croatian border in order to prevent excessive congestions, especially during summer.

Cerar said the guidelines allowed border police to switch to targeted checks when waiting times at the borderer exceeded 15 minutes.

Avramopoulos today noted Slovenia as well as Croatia deemed the guidelines very useful and a very good basis for further cooperation. He announced further guidelines to follow soon.

"In the coming days and weeks we will prepare further guidelines for notification on the decision for the implementation of targeted controls and a technical visit to the border," said the commissioner.

He added that he would visit Slovenia and Croatia himself quite soon.

He made the comments in response to a question about the Commission proposing a new extension of temporary controls in the Austrian-Slovenian border, despite Slovenia's protests the measure is unwarranted.

His comment on the extension was that it was the last extension, and of no more than six months. He said that the measure was justified politically and legally.