Dozens of migrants and refugees were wounded on Sunday when police from Former Yugoslav Republic of Macedonia (FYROM) fired tear gas and rubber bullets at crowds on the Greek side of the border, aid workers said, an act Athens called "dangerous and deplorable."
More than 10,000 migrants and refugees have been stranded at the Greek border outpost of Idomeni since February after a cascade of border shutdowns across the Balkans closed off their route to central and western Europe.
An earlier attempt by a large group of migrants to cross the border fence had resulted in the confrontation, a FYROM official said.
Greece said police on the FYROM side of their joint frontier used teargas, rubber bullets and stun grenades to push back the migrants. FYROM authorities would only confirm they had used tear gas.
A deputy field coordinator with medical charity Medicins Sans Frontieres (MSF) told Reuters that, of around 300 people treated, more than 30 had injuries caused by rubber bullets.
A news release issued by MSF quoted one doctor with the charity saying said three children had been taken in to its field clinic with head injuries caused by rubber bullets.
Police in Skopje said three officers were also hurt.
Over a million people fleeing conflict poured into Europe, mainly through Greece, in the past year. The European Union is implementing an accord under which all new arrivals to Greece will be sent back to Turkey if they do not meet asylum criteria.
A FYROM official who asked to remain anonymous said that a large group of migrants left Idomeni camp on Sunday morning and surged towards the fence.
"They threw rocks at the Macedonian police. The police fired tear gas in response," the official said.
"The migrants were pushing against the fence but standing on the Greek side of the border. The fence is still there, they have not broken through."
Reuters witnesses said a small group of migrants attempted to talk to FYROM border guards, asking for them to open the border. After given a negative response, they and other migrants started walking towards the fence.
FYROM police fired tear gas, and some migrants hurled back some gas canisters and rocks, they said. [Reuters]