PARIS - Five years after Europe's migrant crisis, the European Union is unveiling a long-awaited migration plan Wednesday that stresses mandatory burden sharing - but also sending illegal migrants back to their home countries.

The new so-called migration and asylum pact is the latest effort by the EU's executive arm to create a comprehensive plan for managing migration - and to get all 27 member states behind it.

Backed by Germany, the bloc's most powerful member and the EU's current rotating president, it includes mandatory rules for sharing the migration burden, whether that means hosting asylum seekers or sponsoring returns of failed applicants.

It also aims to strengthen control of Europe's external borders, with new plans to screen all migrants and fast track those unlikely to get asylum, crack down on human trafficking- and increasing support for countries of origin and transit to give people reasons to stay home.

European Commission President Ursula von der Leyen said the plan strikes a fair balance between responsibility and solidarity among member states.

"It is not a question of whether member states should support with solidarity and contributions but how they should support," said von der Leyen.

The commission's plan needs to be approved by the 27 member states, and some European leaders were sounding concerns before its details were even announced.

Migration is a deeply divisive issue in the EU. Countries on the front lines of the migrant influx, like Greece, Spain and Italy, want much more burden sharing and other support. Others, like Hungary and Austria, object to taking in new migrants.

Backdropping the commission's pact was the recent fire at Europe's largest migrant camp on the Greek island of Lesbos. While Germany has agreed to welcome more than 1,500 of the migrants, other countries are taking in far fewer, or none.

Marie De Somer heads the migration program at the Brussels-based European Policy Centre research group.

"The fire in Lesbos was horrible, but one thing that it did do is to showcase to the wider public the urgency and importance of coming to a European solution," she said.

Even though Europe's migration influx has dropped sizably from the million-plus arrivals in 2015 to just 140,000 last year, seven European countries, including EU members Hungary and Croatia, top a new Gallup poll as the world's least accepting countries for migrants.

Analyst Stefan Lehne of Carnegie Europe says, migration promises to be a longstanding issue for Europe.

"The question is how to replace illegal migration - getting into boats and crossing the Mediterranean - by more legal forms of migration. I think this is probably one of the biggest challenges Europe will face in the next 20 to 30 years. There is no silver bullet," said Lehne.

The European Commission says it will unveil proposals on legal migration next year, as well as on Europe's open border Schengen system.