Greek PM threatens to block EU decisions

"Greece will no longer agree to any deal if the burdens and responsibilities are not shared proportionally," he said.

Greece was not invited to a meeting on Wednesday in which Austria and other countries along the Western Balkan migration route agreed to tighten border controls.

Austria last week announced a daily cap on the numbers of people allowed to apply for asylum or travel through to apply elsewhere, prompting some Balkan countries to introduce restrictions.

As a result, migrants have been getting stranded in Greece, the main entry point into Europe.

Tsipras said Austria's behaviour was "unacceptable".

He said it was "shameful" that some countries were refusing to implement joint EU agreements and were instead acting unilaterally.

Greece faces 'chaos'

Tsipras also said he would consult other parties to come to a joint stance ahead of the next EU summit focused on migration on 7 March.

"We need a larger political consensus on this issue," he told MPs, adding: "We will not allow our country to turn into a warehouse of souls, with Europe continuing to function as if nothing is happening."

Tsipras made a similar threat at a summit in February to refuse his support for any agreement unless others pledge to keep borders open.

"We will not tolerate that a number of countries will be building fences and walls at the borders without accepting even a single refugee," Tsipras said, adding that his country would demand the mandatory participation of EU countries in the relocation of refugees.

Hungarian prime minister Viktor Orban announced on Wednesday that he would hold a referendum on mandatory relocation, which his government opposes.

A day earlier, United Nations High Commissioner for Refugees Filippo Grandi warned that border restrictions along the Balkan route go against international and European rules.

“We are worried that these closings are happening and that there are no corresponding openings through relocation and resettlement,” Grandi said, adding that there was a risk of “chaos and confusion” in Greece.

’We want to go’

Earlier on Wednesday Tsipras spoke to German chancellor Angela Merkel on the phone and expressed anger over some EU countries failing to stick to common solutions.

They agreed to intensify efforts to implement EU decisions, and begin Nato operations in the Aegean Sea immediately to counter smuggling networks.

Meanwhile in Greece migrants with young children blocked a Greek motorway on Wednesday along the route to Macedonia, demanding to be allowed to travel further north.

Families chanted "we want to go" after police stopped their convoy at Tempe in central Greece, Reuters reported.

Hundreds are camping out at petrol stations and motels along the route from Athens to Macedonia, where authorities are letting 100 people through at a time.