IDOMENI, Greece

Macedonian special police forces fired stun grenades Friday to disperse thousands of migrants stuck on a no-man’s land with Greece, a day after declaring a state of emergency on its borders to deal with a massive influx of migrants heading north to the European Union.

A crowd of 3,000 migrants who spent night out in the open made several attempts Friday to charge Macedonian police after the border was shut to crossings the previous day. At least eight people were injured in the melee, according to Greek police.

One youngster was bleeding from what appeared to be shrapnel from the stun grenades that were fired directly into the crowd.

Police backed by armored vehicles also spread coils of razor wire over rail tracks used by migrants to cross on foot from Greece to Macedonia.

The migrants, many with babies and young children, spent the chilly and windy night in a dust field without food and with little water. Some ate corn they picked from nearby fields.

“I don’t know why are they doing this to us,” said Mohammad Wahid of Iraq. “I don’t have passport or identity documents. I cannot return and have nowhere to go. I will stay here till the end.”

Greece has seen an unprecedented wave of migrants this year, the vast majority fleeing war and conflict in Syria and Afghanistan. More than 160,000 have arrived so far, mostly crossing over water from the nearby Turkish coast — an influx that has overwhelmed Greek authorities, particularly those on its small islands.

Few, if any, of the migrants arriving want to remain in Greece, a country in the grip of a financial crisis. The vast majority head straight to the country’s northern border with Macedonia, where they cram onto trains and head north through Serbia and Hungary on their way to the more prosperous EU countries such Germany, the Netherlands and those in Scandinavia.

Macedonian police spokesman Ivo Kotevski said both police and the army would control the 30 mile border stretch to stop a “massive” influx of migrants coming from Greece.

“This measure is being introduced for the security of citizens who live in the border areas and for better treatment of the migrants,” he said Thursday.

Until now, the border has been porous, with only a few patrols on each side. Sealing it disrupts the Balkan corridor for migrants who start in Turkey, take boats to Greece or walk to Bulgaria, then make their way through Macedonia or Serbia heading north to the EU.

Almost 39,000 migrants, most of them Syrians, have registered as passing through Macedonia over the past month, double the number from the month before.

“We want to go to Germany to find a new life because everything has been destroyed in Syria,” said Amina Asmani of Syria, holding her husband’s hand and watching her 10-day-old son, who was born on a Greek island during her journey.

She had fought her way past baton-wielding Macedonian riot police in Gevgelija and managed to board a train that took her a step closer to her dream destination: Germany.

“The policemen let us on the train only because they felt sorry for the baby,” she said.

Hundreds more migrants like her are arriving every day on Greece’s islands. The Greek coast guard said Friday it had picked up 620 people in 15 search-and-rescue operations in the last 24 hours off the islands of Lesbos, Samos, Agathonissi, Leros, Farmakonissi, Kos and Megisti. That doesn’t include the hundreds more migrants who have managed to make their own way to the islands in inflatable dinghies.