“I hate you, Hungary! Thank you, Serbia,” said one Iraqi migrant, Hussan, clutching a stone as he rushed to attack the Hungarian police on the border with Serbia.

It was his way of taking revenge after Budapest’s decision to close its frontier to migrants hoping to cross through the country en route to wealthier western European states such as Germany.

“Yalla!” (Let’s go!), young migrants shouted to encourage each other, throwing pieces of asphalt at police at the border before moving into Hungarian territory despite the acrid smell of tear gas.

But choked by the gas, with red eyes streaming, they immediately retreated to recover their strength before continuing the assault.

After more than an hour of clashes Wednesday, dozens of migrants managed in the early evening to overwhelm the Hungarian riot police and enter Hungarian territory from Serbia.

They managed to tear down the fence erected across the two access roads to Hungary and then advanced, ready to do battle with the police who fell back about 50 metres (yards) and responded by throwing tear gas grenades.

For its part, the Hungarian government reported 14 police injured “in clashes with migrants” without giving further details. A Serbian source spoke of several injured among the migrants.

The migrants, mainly from the Middle East including Syria and Iraq, were apparently not taking advantage of crossing into Hungary to vanish but seemed to be seeking to settle scores with the police, who have blocked their journey towards the rich countries of the European Union.

– ‘Freedom, freedom’ –

The two access roads leading to Hungary, usually used by cars, were transformed into a campsite with more than a hundred tents pitched even on the bare asphalt.

In the evening, 20 Serbian police, until then very discreet, intervened to try to bring the migrants to reason.

The Serbian minister responsible for refugees, Aleksandar Vulin, also visited the site to try to calm the situation.

About 500 migrants were at the site, including some 300 who were engaging in skirmishes with cries of “Freedom, freedom” and throwing projectiles.

Some protesters ripped up the pavements bordering the access road at the border for rocks and cobblestones.

Migrants also lit bonfires of clothes and wood, creating clouds of thick smoke.

Two Hungarian helicopters, one army and the other police, flew over the scene.

Children and adults were crying because of the gas, and the Serbian police, who watched the scene without intervening, themselves had to protect their faces with handkerchiefs.

It was the first such incident since Budapest closed the border with Serbia to migrants on Monday night.

About 50 metres from the clashes, Walid, a Syrian from Damascus in his 30s, contemplated the scene while surfing the Internet on his phone.

“Habibi” (My friend!), he said to an AFP journalist, “Is it risky to try to go to Germany through Croatia? Please don’t lie to me.”

More than 300 migrants Wednesday used the Croatian route to northern Europe to circumvent the Hungarian barrier.

At the border post at Roszke, as dusk fell the situation was calm again but the Hungarian riot police remained on the lookout.