Austria has said it will send asylum seekers back to Italy and Slovenia - hours after Angela Merkel agreed to restrict migrant arrivals in Germany to save her coalition.

The German Chancellor struck a compromise deal with her rebellious Bavarian allies, the CSU, last night in a bid to avert a political crisis in Berlin.

Among the proposals is a plan to send back to Austria asylum seekers arriving in Germany who cannot be returned to their countries of entry into the European Union.

But Austria has since said it would be prepared to take similar measures to block asylum seekers at its southern borders with Slovenia and Italy.

The stand-off risks creating a migrant domino effect in Europe with asylum seekers passed back from Germany and eventually ending up back in Italy - where many first enter the bloc.

Italy, under the political control of a populist and anti-immigrant coalition, has recently barred some migrant rescue ships docking in Italian ports.

Austria has said it will send asylum seekers back to Italy and Slovenia just hours after Angela Merkel agreed to restrict migrant arrivals in Germany to save her coalition. Merkel is pictured, today, with the leader of her CSU coalition partners, Interior Minister Horst Seehofer

The German Chancellor (pictured today) struck a compromise deal with her rebellious Bavarian allies, the CSU, last night in a bid to avert a political crisis in Berlin

Austria, under Chancellor Sebastian Kurz (pictured, today), has since said it would be prepared to take similar measures to block asylum seekers at its southern borders with Slovenia and Italy.

EU leaders agreed at last week's summit to build migrant detention centres. Pictured are migrants off the coast in the Strait of Gibraltar

Last night, Angela Merkel agreed an eleventh hour deal on migrants to save her fragile coalition from collapse.

Her party, the Christian Democratic Union (CDU), had been locked in a bitter dispute with coalition partners the Christian Social Union (CSU), whose leader wanted to be able to turn away migrants at the border.

A round of marathon talks on Sunday failed to break the deadlock and ended in the early hours with interior minister Horst Seehofer, the CSU's leader, threatening to resign.

Last night a deal was finally agreed which will keep Mr Seehofer in post and the conservative coalition intact. However, Merkel's other coalition ally, the Social Democrats (SPD) has yet to agree to the plan.

In a pact both sides hailed as a victory, Merkel and Seehofer agreed to tighten border controls and set up closed holding centres to allow the speedy processing of asylum seekers and the repatriations of those who are rejected.

They would either be sent back to EU countries that previously registered them or, in case arrival countries reject this - likely including frontline state Italy - be sent back to Austria, pending an agreement with Vienna.

However, this morning, Austria warned it would 'take measures to protect' its borders.

If the agreement reached Monday evening is approved by the German government as a whole, 'we will be obliged to take measures to avoid disadvantages for Austria and its people,' the Austrian government said in a statement.

It added it would be 'ready to take measures to protect our southern borders in particular,' those with Italy and Slovenia.

'We are now waiting for a rapid clarification of the German position at a federal level,' said the statement, signed by Austria's conservative Chancellor Sebastian Kurz and his allies of the far-right Freedom party, Vice Chancellor Heinz-Christian Strache and Interior Minister Herbert Kickl.

'German considerations prove once again the importance of a common European protection of the external borders,' the statement said.

Angela Merkel and her rebellious Bavarian allies have reached a compromise to end a dispute over managing immigration. Pictured, Interior Minister Horst Seehofer leaves a meeting with the German Chancellor

Kurz on Tuesday is to present before the European Parliament in Strasbourg his priorities for Austria's six-month presidency of the European Union, with the issue of migration expected to feature prominently.

Refugee support group Pro Asyl slammed what it labelled 'detention centres in no-man's land' and charged that German power politics were being played out 'on the backs of those in need of protection'.

Bernd Riexinger of the opposition far-left Die Linke party spoke of 'mass internment camps' as proof that 'humanity got lost along the way' and urged Merkel's other coalition ally, the Social Democrats (SPD), to reject the plan.

Mr Seehofer's party is determined to show that it is tough on migration because it fears losing votes to the far-right Alternative for Deutschland (AfD) party in Bavaria.

As he arrived for more talks with Mrs Merkel, the CSU leader suggested they were in for another long night, telling reporters: 'I hope it will still be light when I go back outside.'

But he later emerged to say the pair had defused their row.

'We have reached an agreement after very intense negotiations,' he said.

Angel Merkel arrives for last-ditch crisis talks with Interior minister Horst Seehofer on Monday

He said the compromise will 'prevent the illegal immigration on the border between Germany and Austria,' with the deal preventing migrants registered elsewhere from entering Germany.

If no agreement had been reached, his party's 70-year partnership with the CDU could have ended.

Mrs Merkel's problems stem from her decision to throw open Germany's borders during the 2015 migration crisis. It led to more than a million migrants arriving in just two years.

Ahead of the meeting, Mr Seehofer had complained to the Sueddeutsche Zeitung newspaper that he was in an 'inconceivable' situation.

Migrant routes to Europe: What are the long and perilous routes thousands of people are taking? Illegal migrants seeking to enter Europe use various long and perilous routes that are evolving as authorities attempt to stem the flow of new arrivals. Here is an overview of how people are reaching the continent. How do migrants reach Europe? Most arrive by crossing the Mediterranean, according to the UN High Commissioner for Refugees (UNHCR), with 172,000 entering through Greece, Italy and Spain last year. The number of arrivals is down sharply from the peak in 2015, when 1.02 million entered Europe via the Mediterranean. Since the start of this year there have been 44,370 arrivals; that is far below the 48,000 who entered Greece over just five days in October 2015. Maltese paramedics aid migrants on board the Lifeline NGO rescue vessel stranded in the Mediterranean with more than 200 migrants as it finally berthed in Valletta, Malta, on 27 June 2018 What are the routes across the Mediterranean? Most of the crossings last year were from Libya or Tunisia into Italy, known as the 'Central Mediterranean' route, says the EU's Frontex border agency. It was used by 118,962 people, mostly Nigerians, Guineans and Ivorians. But arrivals via this route have plunged 75 per cent since a controversial July 2017 deal between Rome and the Libyan coastguard. Crossings have also dropped sharply from Turkey to Greece, the 'Eastern Mediterranean' route. After close to 900,000 migrants in 2015, Frontex recorded only 42,000 last year, essentially Afghans, Iraqis and Syrians. The decline came after a 2016 deal between the EU and Turkey in which Ankara agreed to take back illegal migrants landing on Greek islands in exchange for billions of euros in aid and other incentives. More recently there has been a sharp increase in the use of a route between Morocco and Spain. Nearly abandoned until 2000, this 'Western Mediterranean' route saw 23,000 crossings last year, mostly of Algerians, Ivorians and Moroccans. The number of migrants and refugees using the route to reach Spain stood at 20,992 between January 1 and July 25 according to the International Organization for Migration. This compared to Italy, where just over 19,500 have arrived up to August 23, and at least 13,120 in Greece, according to UNHCR. The renewed popularity of the route is straining Spain's law-enforcement response and its social safety networks. Of the 972 who lost their lives at sea trying to make the crossing to Europe, nearly a third (292) died trying to reach Spain. Other ways into Europe The main secondary route into the EU is through the western Balkans into Eastern Europe. Around 12,000 people entered this way last year, most of them Afghans, Iraqis and Pakistanis - a sharp reduction from the 760,000 in 2015. But this path joins up with one used by migrants who have already passed through Turkey and Greece, meaning the actual numbers of new arrivals don't always add up. Routes into Europe are constantly evolving: according to the French embassy in Slovenia, a new one is developing from Greece through Albania, Croatia and Slovenia, with nearly 1,800 crossings between January and May this year. An 'Arctic route' was briefly in operation 2015 when about 100 migrants crossed a day from Russia into Norway on bicycle. Getting through Africa There are also several routes from African countries to departure points on the Mediterranean, some involving a dangerous crossing of the Sahara desert. A Somali leaving from Mogadishu, for example, could travel via Addis Ababa, Khartoum, Cairo and then Tripoli, ahead of the sea crossing to Europe. An Ivorian leaving from Abidjan might pass via Ouagadougou, Niamey and Agadez - Niger's renowned 'gateway to the Sahara' - to reach Libya. The high human toll The UNHCR says it has registered 16,607 migrants dead or missing at sea since 2014. To this should be added the toll for the perilous Sahara crossing, which the International Organization for Migration says is probably as high as that for the Mediterranean. United for Intercultural Action, a Dutch group which records the identities of victims of the crossings, says at least 34,361 migrants have died trying to reach Europe since 1993. 'Thousands of others have never been found,' it says. Advertisement

'I won't let myself be fired by a chancellor who is only chancellor because of me,' he boasted in an apparent reference to the CSU's traditionally strong election results in Bavaria.

Mrs Merkel's party was 'on the brink' after Seehofer threatened to quit over her handling of Germany's migrant crisis, insiders admitted earlier.

Mrs Merkel, who has been German chancellor since 2005, is facing intense pressure from her Bavarian sister party, who have called for borders to be closed to asylum seekers.

The collapse of Germany's ruling coalition was only averted after she promised Mr Seehofer that she would reach a deal at a summit in Brussels on Friday.

Sources said that he was dissatisfied with what she had achieved and was planning to announce his resignation. Mr Seehofer was said to have blasted the new plan as 'ineffective'.

But he then said he would hold last-ditch talks with Mrs Merkel's CDU on Monday 'in hopes of reaching an understanding'.

Germany's governing coalition took office only in March but Mrs Merkel's Christian Democratic Union and Interior Minister Seehofer's Christian Social Union have had a close partnership for seven decades.

The CSU exists only in Bavaria, the CDU in Germany's other 15 states.

They stay out of each other's territory, but campaign together in national elections and have a joint group in the federal parliament.

If the CSU were to depart the coalition, the government - a so-called 'grand coalition' of Germany's biggest parties - would be left two seats short of a majority in Germany's parliament.

Migrants intercepted aboard dinghies off the coast in the Strait of Gibraltar, are seen on a rescue boat as they arrive at the port of Tarifa, southern Spain yesterday

Key developments in Europe's migration crisis A massive influx of migrants to Europe over the past few years has left thousands drowned and caused deep tensions between nations over how to handle the huge number of arrivals. Here is a look back over the main developments since 2011. 2011 to 2014: Surge with Syria at war The surge in migrant numbers starts in 2011 and steadily increases until 2014 when 280,000 arrive, four times more than the previous year. Most land in Italy and Greece. The UN High Commissioner for Refugees (UNHCR) says more than 3,500 people, fleeing war and misery, died at sea in 2014 alone, mainly in the central Mediterranean. The conflict in Syria, which started in March 2011, leads to a massive exodus of people, mostly to camps in neighbouring countries. The UNHCR says in October 2014 that just over 144,630 Syrians had requested asylum in the EU since 2011, with Germany and Sweden shouldering the burden. It says in June 2014 that 2.5 million people had fled Syria. By April 2018 this figure is at more than 5.6 million, according to the UNHCR website. 2015: More than one million migrants The International Organization for Migration (IOM) says 1,047,000 migrants arrived by sea in Europe in 2015, of whom around 854,000 went to Greece and 154,000 to Italy. The increase is due to the raging Syrian conflict and a deterioration in living conditions in refugee camps. On April 19, 2015 the worst Mediterranean disaster in decades takes place when up to 800 people, mainly from West Africa, die after their crammed fishing boat capsizes in Libyan waters. In 2015 nearly 3,800 deaths at sea are registered by the UNHCR. The war in Syria is credited with kick-starting a wave of migrant movement towards Europe In late summer of 2015, German Chancellor Angela Merkel decides to open Germany's borders to migrants. Some 890,000 arrive over the year and she comes under strong criticism from many of her EU partners. Central and eastern EU nations such as Hungary and Poland refuse outright or resist taking in refugees under an EU quota system. At bursting point, Germany reestablishes border checks, suspending free movement in the EU. Austria, the Czech Republic and Slovakia, all transit countries, follow suit. Hungary and Slovenia, the main entry points to the passport-free Schengen zone, put up fences. Asylum demands peak with 1.26 million demands in the EU in 2015. 2016: Accord with Turkey The EU and Turkey sign a controversial deal in 2016 aimed at stemming the migrant flow to the Aegean Greek islands. Combined with the closure of the so-called Balkans route, the flow drops sharply as Turkey boosts its coastal patrols. Arrivals in Europe fall in 2016 to 390,000, according to the IOM. 2017: Italy on the frontline As the route via Greece and Turkey dries up, Libya becomes the main migration route and Italy the main entry point to Europe. The trend is reversed radically from July 2017 due to accords struck by Rome with the Libyan authorities and militias. After these accords, which involve support to the Libyan coastguards, the number of arrivals in Italy drops by more than 75 percent. 2018: Political crisis in EU In Italy, which has seen around 700,000 migrants arrive since 2013, an anti-migrant coalition including the far right is sworn in to government in June. It refuses to allow the Aquarius rescue ship carrying 630 migrants to dock on its shores; the migrants are taken in by Spain on June 17, after a turbulent week at sea. The case leads to political recriminations and heightened tensions within the EU, particularly between Rome and Paris. In Germany, hardliners in Merkel's conservative bloc on June 18 give her an ultimatum to tighten asylum rules or risk pitching Germany into a political crisis that would also rattle Europe. Advertisement

Mr Seehofer, whose party faces a state election in the autumn, has threatened to turn away migrants whose asylum requests Germany already rejected or who already sought sanctuary elsewhere in Europe.

Mrs Merkel has rejected that approach, saying Germany needs to address migration at an EU-wide level to preserve unity.

EU leaders agreed at last week's summit to build migrant detention centres, but the plan descended into farce as European leaders lined up to refuse to host them. The proposal was billed as an attempt to alleviate pressure on frontline Mediterranean countries, where the vast majority of migrants arrive.

However, French president Emmanuel Macron said he would not host one of the 'controlled centres' and Austria's conservative chancellor Sebastian Kurz mocked the prospect of one being built in his country.

Ahead of the summit, Mrs Merkel had warned that the migration challenge could 'break' the European Union.

In a hard-hitting speech to the Bundestag, Mrs Merkel said the bloc's future was in jeopardy unless an overhaul of migration rules was agreed.

She added: 'Europe has many challenges but that of migration could become the make-or-break one for the EU.'