BRUSSELS (Reuters) - European Union leaders abandoned talks on Friday to find a deal on the bloc's next long-term budget, after failing to agree on the size and shape of cuts to the 1 trillion euro spending plan.

"It's over," one EU official involved in the talks told Reuters. Diplomats from at least three EU delegations at the summit confirmed that the talks had been called off and that negotiations were likely to resume early next year.

The failure to agree a budget for the 2014-2020 period means leaders will have to return to the issue at a later date, with a fresh round of talks most likely in January or February.

Disagreement focused on an inability to find sufficient spending cuts to satisfy all EU member states, particularly Britain and other northern European countries.

(Reporting by Luke Baker; editing by Charlie Dunmore)