Macedonian police fired tear gas and stun grenades to drive migrants and refugees back from its southern border from Greece on Friday but crowds continued to build up at a new bottleneck in an increasingly desperate flight to western Europe.At least 10 people were hurt in the brief flare-up, a day after the impoverished Balkan country declared a state of emergency on its border to halt a daily influx of up to 2,000 Syrians, Afghans, Iraqis and others heading north.When news that several hundred would be let through every few hours reached those on the border, a crush formed after the first group streamed through.Amid screams, at least 10 people fainted and were treated by aid workers, a Reuters witness said. Riot police wielding batons held the line."We have to protect the border and allow entry to only a number of migrants to whom we can offer adequate, humane treatment," said Interior Ministry spokesman Ivo Kotevski.Suleiman, 30, from Pakistan said the police were behaving like those back home. "Shame on them. I lost my son in the crush," he said.Alexandra Krause of the United Nations refugee agency told Reuters: "There are terrible conditions here at the border. The government needs to take control of the situation."Events on Thursday and Friday saw Macedonia become the latest flashpoint of a crisis that has dragged the conflicts of the Middle East - most notably Syria - to Europe's doorstep.After a cold, damp night in the open in no-man's land, hungry and angry crowds tried to force their way into Macedonia early on Friday. Police responded with tear gas and stun grenades, driving them back. Several people bore leg wounds and Medecins Sans Frontieres said it had treated 10 people on the Greek side."The situation is dramatic," said spokeswoman Julia Kourafa. Amnesty International said it had spoken to some refugees who gave accounts of police beatings and shots being fired in the air. Authorities denied being heavy-handed, and began rationing passage later in the day."The police told us to go in small groups, first those with families," said 46 year-old Hassan from Syria. "I'm the happiest man in the world."Even with the limited passage, the numbers stranded in no-man's land and stuck on the Greek side threaten to rise. A record 50,000 reached land by boat from Turkey in July alone.Trying to relieve the pressure on its islands, Greece has begun transporting Syrian refugees by boat to the mainland, from where they head north to Macedonia. A ferry packed with some 2,100 Syrian refugees arrived in Athens from the Aegean islands on Friday.Macedonia says it has registered over 40,000 migrants and refugees entering from Greece in the past two months; most move quickly through the country to Serbia and then walk into Hungary and on to the more affluent countries of western and northern Europe through the borderless Schengen area.But the sight of men, women and children from the Middle East, Africa and Asian sleeping in parks in sleepy border towns has angered some in the Balkans, putting pressure on governments to act.Hungary is racing to complete construction of a fence along its 175 km border with Serbia to keep them out, a step that threatens to create a bottleneck of tens of thousands in Serbia.A UNHCR official on the ground said Greece estimated between 3,000 and 4,000 men, women and children were in the border area.In Geneva, the agency's chief spokeswoman said: "These are refugees in search of protection and must not be stopped from doing so."The refugee wave has diverted some attention from a political crisis rocking the conservative government of Macedonian Prime Minister Nikola Gruevski for most of the year over allegations of illegal wire-taps, corruption and authoritarianism.He now faces an early election in April next year. Some commentators suggested it may play well with voters for the government to be seen taking on Greece for allowing thousands of migrants to pour across its northern border.Macedonia and Greece have long enjoyed an uneasy relationship, rooted in a dispute over Macedonia's name since it broke away from socialist Yugoslavia in 1991. The row has effectively blocked Macedonia's integration with NATO and the European Union.Macedonia has confronted refugee crises before, most notably in 1999 during the war in Serbia's then southern province of Kosovo when hundreds of thousands of ethnic Albanians took shelter in refugee camps on Macedonia's northern border.