"Summary of the nightshift: veto for the extra money to Ukraine," Hungarian Prime Minister Viktor Orbán said after Thursday's talks in Brussels. EU leaders said the aid negotiations would resume early next year.
The aid blocking was announced by Mr Orbán shortly after the EU leaders decided to open membership talks with Ukraine and Moldova and to grant candidate status to Georgia.
Hungary - which maintains close ties with Russia - has long opposed membership for Ukraine but did not veto that move.
Hungary blocks €50bn in EU aid for Ukraine hours after membership talks approved: Viktor Orbán says extra money to Kyiv had been vetoed but talks would resume in the new year »