EU nations on Thursday reached agreement on a long-stalled revision of the bloc's rules to share the hosting of asylum seekers and migrants more equitably.
Sweden, which holds the bloc's rotating presidency, announced the breakthrough after a fraught day of negotiations between EU interior ministers in Luxembourg.
European interior affairs commissioner Ylva Johansson hailed a "hugely significant step" for the EU on migration.
"These are not easy decisions for everyone around the table, but they are historic decisions," said German interior minister Nancy Faeser.
The proposal tabled at the meeting called for compulsory help between EU countries, but with an option of doing that in one of two ways.
The priority is for EU countries to share the hosting of asylum-seekers, taking in many that arrive in nations on the bloc's outer rim, mainly Greece and Italy.
The agreement said nations that refuse would instead be required to pay a sum of 20,000 euros ($21,000) per person into a fund managed by Brussels.
The preliminary agreement opens the way for negotiations with the European Parliament on legislation that could be adopted before European elections in June next year.