Some 1,500 migrants and refugees are estimated to have remained in no-man’s land after the incident.
Emina Cerimovic, of Human Rights Watch, said: “Macedonian authorities should be protecting migrants, not giving the police a green light to fire at them“.
The “western Balkans route” has now become one of the main ways into the EU for the several hundreds of thousands of migrants entering the bloc this year, fleeing war, poverty and persecution in the Middle East, Africa and South Asia.
At least 7,000 people – mostly refugees from the brutal war in Syria – have been registered so far in the last days in overwhelmed Serbia as Europe’s worst refugee crisis in half a century rapidly worsens.
One Afghan couple lost their two children in the chaos, the girl has been returned to them but they are still missing the six-year-old boy: “I need my son” said Mohammed Yasin.
However, later in the evening, police ended up allowing all the migrants into the country after the bid to stop them failed.
Syrian Fatima Hamido, 23, was among those who had slept outside in the rain with nothing to eat, saying: ‘In this Europe, animals are sleeping in beds and we sleep in the rain’.
Machine-gun-toting police backed by armored vehicles spread coils of razor wire over rail tracks used by migrants to cross on foot from Greece to Macedonia, and the army was deployed Friday to the border areas.
Police subsequently seemed to regain control of the situation, stopping the flow of people after hurling a dozen stun grenades in some 30 minutes.
Unlike Serbia, Hungary is an EU member state and therefore a popular crossing point into the bloc, although the country is now building a four-metre (13-foot) barbed wire fence along its 175-kilometre border to stop the influx. Macedonia shut the border to crossings on Thursday.
A day after storming past border checkpoints aimed at keeping them out of the European Union, thousands of migrants – most from Syria, but also some from Iraq and Afghanistan – crowded buses in Macedonia heading north toward the Serbian border. As the some of them rushed towards the fence and tried to open a section of it, to prevent them from opening it the military fired two stun grenades. “Numerous others, they say, are economic migrants”.
“These men are heartless”, said Yousef, a Syrian refugee who gave only his first name, as he held a little wide-eyed girl with curly hair in his arms and pointed toward the policemen.
The Macedonian government criticised Greece for letting the refugees through and even aiding their passage by chartering ships to take them from the Greek islands to mainland Europe.
Conservative prime minister Nikola Gruevski, on the ropes for much of 2015 over a surveillance scandal, faces an early election next April and may win praise at home for taking a hard line on Greece for allowing the migrants through.