Macedonian police fired tear gas and rubber bullets at hundreds of migrants as they tried to break through a border fence on the Greek side of the countries' shared border.
Macedonian officials said a group of migrants left their camp Sunday and stormed toward the fence after rumors had spread through the camp that Macedonia would be opening its border.
When Macedonian police denied this, hundreds of migrants tried to scale the fence, while others threw stones demanding to be allowed to cross.
Police said the incident took place at the Idomeni border crossing in northern Greece where more than 10,000 migrants and refugees have been stranded since mid-February after Balkan nations closed off access to their borders.
Migrants carry a wounded man in a blanket during a protest at the northern Greek border point of Idomeni, Greece, April 10, 2016.
The clashes began soon after some 500 migrants gathered close to the fence. Activists on Saturday had distributed fliers, in Arabic, calling for the migrants to gather at the fence Sunday morning.
A delegation of five migrants asked Macedonian police whether the border was about to open. When Macedonian police denied this, more than 100 hundred migrants, including several children, tried to scale the fence.
Doctors from the medical charity Médecins Sans Frontières said dozens of people were injured, many of them suffering respiratory problems, others with slight injuries from rubber bullets.
Macedonia and other Balkan countries to its north have closed their borders, on what was once the busiest migrant route to central Europe. The European Union has said it will only accept war refugees from Syria and Iraq as well as those from other countries who are eligible for asylum.
Some material for this report came from AP.