Austria's chancellor has warned he will close his country's borders if Germany shuts its southern frontier in response to the migrant crisis.

The threat comes as more than half of the European Union's leaders meet in Brussels today to grapple with a resurgent political crisis over migration that threatens to tear the bloc apart.

Chancellor Sebastian Kurz said he would 'be ready and do everything necessary to protect our borders' if Horst Seehofer, Germany's interior minister, goes ahead with plans to protect his country's southern boundary.

He added: 'That would mean securing the border on the Brenner [Pass] and other locations... [though] I want to help ensure it doesn't get that far.'

Chancellor Sebastian Kurz said he would 'be ready and do everything necessary to protect our borders' if Horst Seehofer, Germany's interior minister, goes ahead with plans to protect his country's southern boundary

European leaders pose for a picture at the informal meeting on migration and asylum issues

Horst Seehofer, Germany's interior minister has pledged to shut Germany's southern frontier to migrants if Chancellor Angela Merkel does not find a solution to the crisis by the end of June

Angela Merkel is welcomed by European Commission President Jean-Claude Juncker at the meeting on Sunday

The Mission Lifeline said the vessel was stranded in international waters of Malta. The island nation's military provided humanitarian assistance but the ship was not allowed to land there

Now facing a political crisis, Merkel's interior minister, Seehofer (pictured), has given her until the end of the month to find a European deal to curb new arrivals

The Mission Lifeline is a Dutch-registered ship that is run by a German charity of the same name. There are 234 migrants on board the ship

Matteo Salvini (center) regards rescue boats as a taxi service doing the work of people smugglers and said the migrants on the Mission Lifeline would 'only see Italy on a postcard'

Seehofer has pledged to shut Germany's southern frontier to migrants if Chancellor Angela Merkel does not find a solution to the crisis by the end of June.

That dispute within the German coalition has prompted worries within the EU that there will be a domino effect of member nations tightening their borders.

Austria has suggested that Albania could be used to process illegal migrants outside of the EU before sending them 'back to their countries of origin as soon as possible'.

Chancellor Kurz confirmed Austria is working with Denmark and other countries to work out a solution to the migration crisis involving non-EU members.

Later today, 16 heads of government and state are responding to alarm about growing rifts not only among the EU's 28 members but also within the German government itself, the bloc's most powerful nation.

As tensions rise between Rome and Paris as well as Rome and Berlin, the top-level talks are designed to help clear the heavy air for a previously scheduled full summit of all EU leaders on Thursday and Friday.

But Chancellor Merkel has conceded 'no solution will be reached' on the overall migration issue at either summit.

Political developments in Italy, a major migrant landing point, and in Germany, their top destination, have brought the EU's political crisis back.

Since assuming office several weeks ago, Italy's new populist government has refused to admit foreign-flagged charity ships packed with hundreds of migrants.

After turning away the Aquarius, which later docked in Spain, Rome vowed on Saturday it would block the Lifeline, a German vessel with more than 230 people aboard.

Reflecting popular anger over the failure of EU member states for years to shoulder more of the migrant burden, Rome has pledged not to take in one more asylum-seeker.

Italy's stance has raised tension both with Germany and within Merkel's coalition government, with EU diplomats saying the mini-summit is to help 'save' the chancellor.

With a backlash over her open-door policy toward asylum-seekers, Merkel has emerged weakened in recent elections.

Now facing a political crisis, Merkel's interior minister, Seehofer, has given her until the end of the month to find a European deal to curb new arrivals.

Italian Prime Minister Giuseppe (left) and French President Emmanuel Macron (right) talk as they attend at the informal meeting on migration and asylum issues in Brussels

Sixteen heads of state from across Europea gathered in Brussels on Sunday to discuss growing rifts in immigration policy

Migrants on an inflatable boat being rescued before boarding the Mission Lifeline on June 21

If that fails, he vowed to order border police to turn back migrants, which means many will likely have to return to Italy.

Under the so-called Dublin rules, asylum-seekers must be processed in the country where they first arrive, often Mediterranean countries like Italy, Greece and Spain.

EU leaders last December had set the end of June as a deadline to reform the rules by establishing a permanent mechanism to relocate asylum-seekers throughout the bloc.

With such reform elusive, Merkel is now pushing for bilateral, trilateral and multilateral deals.

Merkel also got Italian Prime Minister Giuseppe Conte to attend the mini-summit by telling him pre-written conclusions had been withdrawn, Italian officials said.

Draft conclusions included calls to speed up returns to countries tasked with processing them, such as Italy.

Rome on Saturday accused French President Emmanuel Macron of 'arrogance' for turning back migrants at the French-Italian border.

France's human rights ombudsman Jacques Toubon also criticised the French response to the Aquarius crisis, telling the Journal du Dimanche newspaper that the migrants should have been allowed to enter the country.

Macron and Spanish Prime Minister Pedro Sanchez, due in Brussels Sunday, also proposed closed centres in arrival countries to hold asylum-seekers until claims are processed.

EU diplomats and sources said the talks will also tackle how to strengthen the bloc's external borders, where consensus exists.

EU cooperation deals with Turkey and Libya, the main transit countries, have sharply cut, at least for now, the flow of migrants to Europe since 2015.

The leaders are also to discuss proposals for reception centres outside the bloc to separate genuine war refugees from economic migrants, who can be sent home.

Malta Armed Forces sends aid to the ship Lifeline, near Malta in International Waters June 23

Maltese armed forces provided humanitarian supplies to the Lifeline vessel but refused to let it dock

Migrants are seen on the ship Lifeline while the Malta Armed Forces arrive to send aid, near Malta in International Waters

Migrants from sub-Saharan Africa rest after arriving to the port of Tarifa, near Cadiz, southern Spain, left. Migrants are pictured right on a boat arrive at the the port

A girl is helped by medical staff after landing. Spanish authorities say they have rescued 264 people in 16 boats in the Strait of Gibraltar.

But with fears of new migrant surges in the future, diplomats warn the asylum reform impasse could destroy the EU's signature Schengen system of borderless travel.

'The situation is risky,' a diplomat said.

Rounding out the 16 leaders, EU officials said, are those from Austria, Greece, Malta, Bulgaria, Belgium, the Netherlands, Croatia, Slovenia, Denmark, Finland, Sweden and Luxembourg.

Seehofer is allied with Austria's Kurz, whose country on July 1 takes over from Bulgaria the six-month rotating EU presidency.

Staying away are the leaders of Hungary, Poland, the Czech Republic and Slovakia, who have for years opposed mass migration.