Hungary has blocked a joint contribution by EU nations to a "Summit for Democracy" organized by US President Joe Biden, diplomatic sources told dpa on Friday.
Diplomats in Brussels said Budapest had exercised its veto right because Hungarian Prime Minister Viktor Orban had been the only EU leader not to be invited to next week's online meeting.
However, they added that another attempt by Orban's government to prevent European Commission President Ursula von der Leyen and European Council President Charles Michel from attending had failed, after a legal opinion found that the top officials could participate even against the will of a member state.
Biden's summit, taking place next Thursday and Friday, has three key themes: "defending against authoritarianism," "fighting corruption" and "promoting respect for human rights."
Orban has been accused by critics of falling far short in those areas.
Diplomats acknowledged that the Hungarian government's moves to block EU participation hardly came as a surprise, noting that the decision to leave out Budapest while inviting every other EU nation had been seen as a considerable snub.
The EU's joint contribution to the summit had been meant to take the form of a position paper, addressing the main items on the agenda. This had already been negotiated at a working level.