United Nations: UN Secretary-General Ban Ki-moon on Wednesday slammed Hungary’s treatment of migrants as unacceptable after police fired tear gas and water cannon at asylum-seekers at its border with Serbia.

‘I was shocked to see how these refugees and migrants were treated. It’s not acceptable,’ Ban told a news conference in response to a question about the border clashes.

The UN chief stressed that ‘these were people fleeing war and persecution’ and that the response must be one of ‘compassionate leadership.’ ‘We must show them caring hands,’ he said. ‘They must be treated with human dignity.’

On Wednesday, Hungarian police clashed for hours with hundreds of migrants after the government sealed its southern border with Serbia, one of the biggest entry points into the European Union.

Police fired at least 20 tear gas grenades as the crowd chanted slogans in Arabic with their fists in the air. Children were crying from the effects of the tear gas and several ambulances were dispatched to the border crossing, according to AFP reporters at the scene.

The United Nations has made repeated appeals to European leaders to uphold human rights as the continent grapples with its worst migration crisis since World War II.

Europe’s migration crisis is expected to loom large over this year’s gathering of world leaders at the United Nations, which kicks off on 25 September with an address by Pope Francis.

Ban has called a meeting on Sep 30 on the sidelines of the UN General Assembly to ramp up the international response that the UN chief said should be ‘humane, effective and rights-based.’

The secretary-general praised Lebanon, Jordan and Turkey for taking in millions of refugees from the war in Syria, which is now in its fifth year. He cited Germany, Sweden and Austria ‘for opening up doors and showing solidarity’ and applauded Britain and Kuwait for providing financial aid to address the refugee crisis.

But he made clear that other European countries were lacking in their response. ‘I ask those standing in the way of the rights of refugees to stand in their shoes,’ he said.

‘People facing barrel bombs and brutality in their country will continue to seek life in another. People with few prospects at home will continue to seek opportunity elsewhere. This is natural. It is what any of us would do for ourselves and for our children.’