LESBOS/IDOMENI: Border closures by European states alarmed by the migration crisis will cause “further chaos and confusion,” the new head of the UN refugee agency warned on Tuesday.

“I am very worried about the news that we are getting about increasing closures of European borders along the Balkans route because that will create further chaos and confusion,” UNHCR chief Filippo Grandi said during a visit to the Greek island of Lesbos.

Some 8,000 refugees and migrants have been trapped in Greece after Macedonia on Sunday barred passage to Afghans and introduced tougher document checks for Syrians and Iraqis.

This followed a decision by countries further up the migrant route to turn back groups of Afghans.

“It will increase the burden on Greece which is already shouldering a very big responsibility in managing these people and this is happening when we are not yet having alternatives,” Grandi said after visiting the Lesbos migrant registration point, or hotspot.

Meanwhile, Greece made a strongly worded complaint to Austria Tuesday for drastically restricting migrant crossings, as police at the Greek border with Macedonia removed hundreds of Afghan migrants stranded at a camp there.

Athens has criticized Austria’s decision last week to cap the daily number of asylum applications and migrants crossing the country — an action that has left thousands stranded in Greece.

The Austrian ambassador to Greece was summoned to the foreign ministry to receive the complaint Tuesday after Austria invited officials from western Balkan countries to a meeting on migration in Vienna Wednesday, excluding Greece.

The ministry described the meeting as a “unilateral move which is not at all friendly toward our country.”

More than 1 million migrants and refugees reached the EU last year, with more than 80 percent of them traveling from Turkey to nearby Greek islands. Arrivals have continued this year at an average of 4,000 each day

He said take up of an EU program to relocate some 160,000 people from Greece and Italy to other member states is “too small” and another scheme to directly resettle refugees from Turkey “has not started yet.”

“So... to close the borders or to manage them tightly, to put it that way, in the absence of legal, safe alternatives for refugees will increase chaos and most likely will increase irregular movements that put people at risk,” the Italian diplomat said.

Lesbos is the main landing point for thousands of refugees and migrants who brave a perilous crossing from neighboring Turkey in search of a better future in Europe.