Thousands of Syrians, Afghans and others seeking sanctuary were caught up in chaotic scenes on Friday as they tried to cross the border from Greece into the former Yugoslav Republic of Macedonia (FYROM).
Tension erupted in Europe’s migrant crisis as Macedonian riot police fired tear gas and stun grenades in a bid to disperse the crowds.
At least eight people were reported injured.
After declaring a state of emergency and effectively blocking its southern border to migrants, FYROM hours later allowed hundreds through to continue their journey towards Western Europe by train.
Up to 2,000 migrants a day have been crossing into FYROM from Greece in recent weeks, before heading north to Hungary and Europe’s borderless Schengen zone.
But Macedonia is struggling to cope and on Friday morning tensions flared with the crackdown by security forces on the border.
The UN refugee agency voiced concern at the measures used by Macedonia’s riot police.
It urged the Skopje government to establish “orderly management” of its borders.
UN High Commissioner for Refugees Antonio Guterres spoke to the Macedonian foreign minister and “received assurances that the border will not be closed in the future”, the Geneva-based agency said in a statement.
UNHCR also called on authorities in Greece to provide urgent assistance to “people stranded on the Greek side of the border” and to help them move towards refugee reception facilities further from the border with its Balkan neighbour.