Poland and Hungary's refusal to endorse a widely supported revision of the EU's asylum rules left a summit of the bloc's leaders that ended on Friday soaring, undermining cooperation on other issues such as Ukraine.

A summit declaration that would have codified the general EU agreement for member states to share the hosting of asylum-seekers -- or pay those who do -- was rejected by Warsaw and Budapest.

As a result, the summit's chair, European President Charles Michel, was forced to issue a statement in his own name promising that "work will be stepped up" on the issue of immigration while mentioning Poland and Hungary's opposition.

The preliminary June 8 agreement to revise asylum rules, which was approved by a large majority of EU countries, was dubbed a "watershed", and European Commission President Ursula von der Leyen predicted that it would become law by the end of the year.

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Migration dispute 

The migration dispute dominated the summit, but Poland and Hungary's stance appeared unlikely to derail the EU agreement to share the burden when it came to asylum seekers.

Polish Prime Minister Mateusz Morawiecki stated that "forced relocations" of migrants should not be included in the summit text, and he linked the issue of migration to the violence erupting in France.

"Put these two images together: that of Paris suburbs today, with big riots, the looting of stores, broken windows, cars on fire," against "calm Polish towns.... The image that we are defending is probably obvious: Poland has chosen security, peace, and public order," he said.

The EU disagreement was taking place in the aftermath of the June 14 sinking of an overcrowded migrant boat off the coast of Greece, in which at least 82 people died.

Lighthouse Reports, a Dutch-based human-rights organization, accused Greek authorities of tampering with survivors' testimony in order to avoid allegations made by some survivors that the tragedy occurred because the Greek coast guard tied a rope to the vessel and powered away, causing it to capsize.

Survivors told AFP that Greek authorities pressured them not to speak to the media and not to blame the capsizing on the Greek coast guard.