Hungary has blocked €50bn ($55bn; £43bn) in EU aid for Ukraine hours after agreement was reached on starting membership talks.
“Summary of the nightshift: veto for the extra money to Ukraine,” Hungarian Prime Minister Viktor Orban posted on social media after talks in Brussels.
EU leaders said talks on aid for Ukraine would resume early next year.
Ukraine is critically dependant on EU and US funding as it continues to fight occupying Russian forces.
Poland has a very pro EU government led by Donald Tusk now.