Macedonian police have fired a round of tear gas to disperse a group of stranded migrants protesting on the Greek side of the razor wire fence dividing the two countries.
Reports said small-scale scuffles broke out when about 50 migrants approached the fence in protest on April 13.
The unrest ended when Greek riot police stepped in to move back the migrants from the fence, reports said.
The incident took place as Macedonian President Gjorge Ivanov and his Croatian and Slovenian counterparts were visiting the Gevgelija reception center just a few hundred meters away.
Hundreds of migrants were wounded on April 10 in clashes with Macedonian police, who fired tear gas and rubber bullets after a group tried to storm the border.
Macedonia accused Greek police of failing to intervene to prevent around 3,000 people trying to illegally enter its territory, but Athens said Skopje had used "excessive force."
It was the latest bout of unrest at Idomeni, where thousands of migrants have found themselves stranded after Macedonia and other Balkan states denied them passage to Germany and other destinations in northern Europe.