Commission attacks Tusk on 'anti-European' migrant plan

"It denies, it ignores, all the work that we have done during the past three years," said Avramopoulos.

Avramopoulos said the Tusk paper also undermines "one of the main pillars of the European project, the principal of solidarity".

He said "solidarity cannot be cherry picked" and that Europe has a moral and legal duty to protect refugees.

The unusually frank comments come ahead of discussions on migration on Thursday among EU leaders at a summit in Brussels.

Tusk in a paper tells the leaders that the mandatory quotas, as proposed by the commission under broader asylum reforms, are both "highly divisive" and "turned out to be ineffective."

Tusk made similar comments in October when he announced that obligatory quotas have "no future" given the outright defiance from the so-called Visegrad group of countries composed of the Czech Republic, Hungary, Poland, and Slovakia.

A two-year relocation scheme of asylum seekers from Greece and Italy to other EU states ended with the commission taking the Czech Republic, Hungary and Poland to the EU's top court in Luxembourg last week.

All three balked at taking in asylum seekers.

Italy and Visegrad to meet Thursday

The issue of mandatory quotas, which the commission views as a key component of an EU-wide solidarity reform known as Dublin, has so far failed to reach any consensus among bickering member states.

Hungary, the Czech Republic and Slovakia had voted against the relocation mechanism in 2015 but were required to take in people anyway. The issue was viewed in the respective states through a prism of sovereignty and security.

"Tusk believes that things as they stand now, it is difficult now to find a consensus based on the mandatory quota," a senior EU official told reporters in Brussels on Tuesday.

He said that the voting process that led to the 2015 mandatory relocation scheme had instead "contributed to further divisions".

Italy and Greece are leading EU states that are at odds with the Visegrad group, and are pushing for greater commitments to ease pressure of migratory flows, given that most people enter either Italy or Greece first before heading further north in Europe.

On Thursday, Italy along with the Visegrad group of member states will meet to discuss solidarity - but in terms of getting more EU states to shore up funding for the EU trust fund for Africa.

The EU official said the meeting "will demonstrate solidarity, not in the form of relocation, but in the form the trust fund."

The fund has some €3.3 billion, of which EU states, including Norway and Switzerland, have only pledged around €375 million.

Bulgaria, which will take the helm of the upcoming EU presidency, has contributed only €50,000.