European Union foreign ministers meeting in Brussels have failed to break the deadlock over the thorny question of how quickly the EU's doors should open to foreign workers when new members join in the coming years.
A transition period of up to seven years had been proposed. But Spain has now lodged objections which have held up agreement.
Until now it has been Germany and Austria—which have long borders with countries hoping to join the EU—that have held up agreement on this difficult issue.
Most applicant countries want their people to have the right to cross borders and seek work in existing EU states as quickly as possible. But Germany and Austria in particular fear an influx of cheap labour causing problems for their own populations.
To satisfy them, the European Commission and the Swedish Government, which holds the EU's rotating presidency, came up with a proposal for flexible transition periods.
It would allow countries with most to fear to keep their borders closed for up to seven years while other member states could open up much earlier.
But Spain, lodging its objections, argued there was no need for long transition periods.
One diplomat said Spain was posing as the accession countries' friend, but in reality was holding out for a better deal on another matter —the allocation of aid funds to Europe's poorer regions.
Spain has benefited hugely from these grants and fears losing out when new countries join the EU.
The two issues—the free movement of labour and regional funds—are, in theory, separate but they may have to be solved together.