Macedonia has started letting a limited number of migrants to cross the border from Greece after riot police fired stun grenades at a crowd demanding entry.
The would-be immigrants stuck in a no-man's land on the border apparently tried to surge early Friday across police lines.
Police responded with stun grenades. A medical team from Doctors Without Borders reports 10 people were injured, saying four needed to go to a hospital. Macedonian police denied reports that they also fired tear gas, but they did lay razor wire across the railroad tracks migrants have used to enter the country by foot.
Later, the Macedonian interior ministry said it would allow a limited number of what it called "vulnerable" migrants to enter the country and would help them "in accordance with the state's capacities."
It did not say what the vulnerable categories are.
The United Nations says more than 160,000 migrants have arrived in Greece so far this year. They are trying to make it to EU countries through Macedonia and Serbia. Around 2,000 migrants a day have been crossing into Macedonia from Greece.
Nearly all are from Afghanistan, Iraq and Syria. They are trying to flee war, terrorism, and poverty for a better life in the wealthier European Union.
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Many of the migrants say there is an extra urgency right now to get to the West before Hungary completes a fence along its borders.
Macedonia declared a state of emergency Thursday and deployed soldiers to the border with Greece to stop the wave of arrivals.
The U.N. refugee office says while it understands the security concerns and pressures on Macedonia, it is concerned about the "increasingly precarious situation" along the border with Greece.
It urges both countries to help people it says are in need of international protection.