The leaders of more than half of the EU's member states on Thursday declared their support for defending the rights of LGBTQ people after a controversial law passed in Hungary. 

Without directly mentioning Hungary, a letter signed by the heads of state ahead of an EU summit deplored the "threats against fundamental rights, and in particular the principle of non-discrimination on grounds of sexual orientation".

This was a cloaked reference to the law, which bans LGBTQ educational content for children and is due to come into effect in Hungary soon. 

The debate about the law has divided EU countries largely along an east-west line with more socially conservative governments in eastern Europe so far unwilling to come out against Hungary's right-wing Prime Minister Viktor Orban.

The issue pushed to the forefront of EU politics this week when UEFA, Europe's football governing body, rejected a plan by Munich to light up its stadium in LGBTQ rainbow colours for a Germany-Hungary match on Wednesday.

The city reacted by instead decorating many of its monuments - including those next to the stadium - in rainbow tints while French President Emmanuel Macron said UEFA's decision was deeply regrettable. 

The controversy will likely be raised during a summit working dinner in Brussels later on Thursday.

The signatories are the leaders of the following countries: Belgium, Denmark, Germany, Estonia, Ireland, Greece, Spain, France, Italy, Cyprus, Latvia, Luxembourg, Malta, the Netherlands, Finland and Sweden. 

Austrian Chancellor Sebastian Kurz, who sometimes aligns with Orban on social issues, was missing, but his Luxembourg counterpart Xavier Bettel said on Twitter that Kurz "also joined us this morning with his signature".